Many of us now work at desk jobs which require the expenditure of very little physical energy but need a lot of mental concentration.  This sedentary lifestyle could certainly be adding to the overweight/obesity increases occurring in the UK and beyond.  If we take in more calories than we use then the excess is stored in the body and our waist-lines expand.  However, a very interesting study(1) has just been published which suggests that desk-jobs requiring mental, but not physical, activity could be affecting our body chemistry in ways that may lead to our overeating.  If this extra energy consumption is not then expended through exercise it can lead to weight gain.

An earlier, preliminary, study(2) by the same authors last year found that knowledge-based work, sitting for 45minutes reading a document and writing a 350 word summary using a computer, required an average of only 3 calories more energy than resting in a sitting position for 45minutes.  However, after the knowledge-based work individuals consumed 229calories more (at an unrestricted buffet) than after 45 minutes rest.  According to the assessment questions, markers of appetite sensation had not changed between the two sitting conditions.  In addition to this, the test subjects did not compensate by decreasing food intake or increasing energy expenditure for the rest of the day. 

The researchers wanted to look deeper at the phenomenon and hence their most recent study(1).  In this small experiment the researchers investigated 14 women (who were not over- or underweight).  Each individual went through the following 45minute test ‘conditions’
-Resting in a sitting position
-Reading a document and writing a summary on the computer
-Performing a number of different computerised tests
The blood (plasma) glucose levels, insulin levels and cortisol (a hormone) levels were measured seven times during each experimental condition.  Appetite sensations were also measured via a questionnaire and following the tests there was a buffet where the participants could eat what they liked.

After the reading/writing test the individuals ate, on average, 203 calories more than they did after rest.  After the computerised tests they ate an average of 254 calories more than they did after a 45minute rest.  There was no difference in the appetite sensations recorded among the three different test conditions.  In summary the study(1) showed that knowledge-based mental work induces significant increases in calorie intake which could, over a long-term period, be a risk factor for overweight. 

The interesting point is that there was also a difference between the body chemistry measured.  The average cortisol levels were significantly higher in the two knowledge-based work conditions (the reading/writing and computerised test) compared to the rest condition.  There was also a significant increase in variations in glucose and insulin levels compared to rest.  These biochemical markers can provide insight into why mental work can induce overeating.  They also present possible solutions!!

The fluctuating cortisol, glucose and insulin levels could be the trigger for over eating.  Cortisol is often known as the stress hormone.  Under periods of pressure our cortisol levels rise and there is suggestion that high levels can unbalance blood sugar control in the body (which has knock-on effects for the amount we consume).  The fluctuating glucose and insulin levels may well be contributing to over-eating.  The body is a very clever machine!  Our brain uses glucose in order to function, so perhaps the fluctuations are triggering increased food intake.  The problem is that; since we are not increasing physical activity there is a calorie over compensation and the extra food we take in to balance out the blood sugar fluctuations is not expended by increased physical activity.
 

Personally I think the key for desk-based workers is to try and provide the body with a slow and steady supply of energy throughout the day, this should prevent the blood sugar fluctuations which may be leading to over-eating.  My advice would be to start the day with a breakfast containing a protein source e.g. an egg/nuts/seeds/yoghurt (be wary of low fat yoghurt as these are often packed full of added sugar) together with some unrefined carbohydrate which releases sugar slowly (one that has a low glycaemic index) such as oats or some fruit salad.  If you can avoid caffeinated tea or coffee then this could also help.  The caffeine can disrupt blood sugar balance.  The lunchtime sandwich often leads to a mid-afternoon energy slump that leave us reaching for a sugar fix.  Bread is starchy and releases sugar very quickly into the bloodstream.  The body responds with a surge of insulin which can cause a subsequent sugar low a few hours later at mid-afternoon and consequent feelings of lethargy.  It may be preferable to try basing your lunchtime meal around a portion of protein (unprocessed meat, fish, eggs, beans) together with 2-3 portions of vegetables/salad.  This kind of meal will provide the body with a steady source of energy throughout the afternoon.  If you do find your energy levels dropping try eating a few unsalted/un-blanched nuts.

Desk work needn’t cause havoc with our waistlines!  Of course, trying to take some kind of daily exercise is also very important.  Even a half hour walk or taking the stairs, it all helps.  Exercise also helps to regulate appetite and food intake.  A holistic approach is certainly the way to go!

(1)Chaput JP et al.  2008.  Glycemic instability and spontaneous energy intake:association with knowledge-based work.  Psychosom Med.  [E-pub before print August 25 ] doi:10.1097/PSY.0b013e31818426fa
(2)Chaput JP&Tremblay A.  2007.  Acute effects of knowledge-based work on feeding behavior and energy intake.  Physiol Behav.  90:66-72

Written by Ani Kowal

Continuing with the theme of child health I have decided to look at the prevention of common infections such as those of the ear, nose and throat, and tummy upsets.  Children returning to school after the long holiday break will be exposed to others who they may not have seen in weeks and also to the various ‘bugs’ that they may be carrying.  Fear not, it is not inevitable that your children will end up feeling poorly and catching every illness around them! 

A healthy, strong immune system will help to prevent various infections, or keep them short and less intense if they do occur.  Ensuring that your child is eating healthily will mean that they are getting all the vitamins, minerals and essential fatty acids they need in order to keep their immune system fighting fit.  However, I am aware that many children are not regularly getting the recommended daily 5 portions of fruit and vegetables.  This may mean that they are lacking in essential nutrients and their immune system may not be running at optimum.  Certain supplements, specially formulated for children, may be helpful in supporting a healthy diet in order to keep the immune system healthy.  However, a supplement cannot be seen as a replacement for the foundations provided by a healthy lifestyle.

Here I will be looking at some of the evidence which suggests that a multivitamin and mineral supplement taken together with a fish oil supplement (to provide essential omega 3 fatty acids) and a pre/pro-biotic supplement could be useful in helping to prevent childhood infections. 

Two papers have been published by a group of researchers who used a fish oil and multivitamin-mineral supplement in children who regularly suffered from recurrent ear(1) and sinus(2) infections.  The studies were very small and preliminary but both suggested benefit in the prevention of these common childhood conditions.  The researchers suggest that such preventative treatments could reduce the need for prescribed antibiotics.  Evidence also exists to suggest that individuals who suffer from recurrent tonsillitis infections may have a disturbed balance of various vitamins(3,4) and minerals(5), especially lowered zinc levels.

Previously I have written about zinc and vitamin C in relation to the prevention and shortening of the common cold and I would recommend you visit this post for more information. 

A few months ago I wrote about the importance of maintaining a good balance of ‘friendly’ bacteria in the digestive system in order to boost immune function and how evidence suggests that taking a daily probiotic supplement may prevent the occurrence of the common cold.  Children who have suffered from recurrent infections will normally have been exposed to frequent courses of antibiotics.  Antibiotics may indeed have been useful for fighting the bacterial infection, however they also kill many of the beneficial bacteria that would normally live in a healthy gut.  This imbalance could lead to a less efficient immune system and an increased likelihood of further infections.  One study(6) revealed that; in children with acute infections of the upper and lower respiratory tract, such as bronchitis and pneumonia, a probiotic supplement seemed helpful in regulating the immune system.  A recent review paper(7) indicated that probiotics also have immune enhancing effects in children and may prevent infections and diarrhoea. 

A daily supplement containing probiotics and prebiotics (such as FOS fructooligosaccharides) may be worth considering.  For more information on prebiotics and probiotics I would suggest visiting the post on irritable bowel syndrome which defines and explains these supplements.

When considering multi-nutrient supplements I would suggest a child-specific ‘food-state’ supplement as these will be easily absorbed by the body.  Again I would like to stress that supplements should not be seen as a substitute for a healthy, balanced diet plentiful in a variety of colourful fruits, vegetables and healthy fats. 

Best wishes to all children for an enjoyable first term back at school!

(1)Linday LA, Dolitsky JN, Shindledecker RD, Pippenger CE. 2002.  Lemon-flavored cod liver oil and a multivitamin-mineral supplement for the secondary prevention of otitis media in young children: pilot research. Ann Otol Rhinol Laryngol.  111(7 Pt 1):642-52.
(2)Linday LA, Dolitsky JN, Shindledecker RD.  2004.  Nutritional supplements as adjunctive therapy for children with chronic/recurrent sinusitis: pilot research. Int J Pediatr Otorhinolaryngol.  68(6):785-93.
(3)Aleszczyk J et al.  2001.  [Evaluation of vitamin and immune status of patients with chronic palatal tonsillitis][Polish Article].  Otolaryngol Pol.  55:65-67
(4)Shukla GK et al.  1998.  Comparative status of oxidative damage and antioxidant enzymes in chronic tonsillitis patients.  Boll Chim Farm.  137:206-209
(5)Onerci M et al.  1997.  Trace elements in children whith chronic and recurrent tonsillitis.  Int J Pediatr Otorhinolaryngol.  41:47-51
(6)Lykova EA, Vorob'ev AA, Bokovoi AG, Murashova AO.  2001.  [Impaired interferon status in children with acute respiratory infection and its correction with bifidumbacterin-forte] [Article in Russian].  Zh Mikrobiol Epidemiol Immunobiol.   Mar-Apr;(2):65-7 
(7)Nova E, Wärnberg J, Gómez-Martínez S, Díaz LE, Romeo J, Marcos A. Immunomodulatory effects of probiotics in different stages of life. Br J Nutr. 2007 Oct;98 Suppl 1:S90-5.

Written by Ani Kowal

The long summer holidays have ended and children are heading back into their classrooms.  Over the last few years the press have been giving increasing coverage to a condition known as ADHD (attention deficit hyperactivity disorder).  Today I would like to write about essential fatty acids, one of the many nutritional aspects associated with the condition. 

The following facts were provided by a fantastic charity – Food for the Brain(1) – a non-profit educational charity, created by a group of nutritionists, doctors, psychiatrists, psychologists, teachers and scientists to promote the link between nutrition and mental health.

 
-Children with ADHD often have three basic problems, they can't pay attention, they are hyperactive and they act on impulse.
-It is estimated that up to 5% of school-age children in England and Wales have ADHD – representing around 67,000 children.
-In a class of 30 children there will be one or two children with ADHD.
-Boys seem more likely to have ADHD than girls.
-In the UK, between three and nine boys are diagnosed with ADHD for every girl diagnosed, this may be because boys and girls tend to have different symptoms of ADHD.
-Inattention is more common among girls while hyperactivity is more common among boys.  A boy who is hyperactive (shouting, running about and getting into trouble) may be more noticeable than a girl who is inattentive (daydreaming, forgetful and easily distracted).
-It is estimated that between 30% and 70% of children with ADHD continue to exhibit symptoms in the adult years.

In this blog post I am going to concentrate on the potential usefulness of long chain omega 3 fatty acids (EPA and DHA found in oily fish such as salmon, mackerel, sardines) in the management of ADHD.  These essential fatty acids are crucial to brain development and brain function and increasing evidence indicates that deficiencies or metabolic imbalances of these fatty acids might be associated with childhood developmental and psychiatric disorders including ADHD. Omega-3 are often lacking in modern diets and as I will discuss here, preliminary evidence suggests that supplementation may well be helpful in the management of ADHD and linked behavioural and learning difficulties (such as dyslexia and dysphraxia).

Children with ADHD are often found to have nutrient deficiencies, especially in essential fatty acids(2,3,4). Common symptoms of deficiency may include dry, flaky skin, frequent urination and excessive thirst.  However, symptoms vary or may be absent altogether.

Clinical trials with nutrients and behaviour problems are not easy to conduct as the diagnosis and tracking relies on behavioural criteria and trials do not allow for individual tailoring of treatments.  The data for nutritional management of ADHD is still preliminary but growing rapidly.  Personally I see the links as being exceptionally strong and I know that many other health professionals feel the same way as I do.  The brain needs optimal nutrition to function effectively.  If we are not getting enough vitamins, minerals and essential fatty acids from our diets then we are bound not to be at our best!

One of the leading researchers into learning/behavioural difficulties and nutritional supplementation in the UK is Dr Alexandra Richardson.  Dr Richardson is an inspiration and I have been privileged enough to hear her speak on a number of occasions.  In 2002 she published a paper(5) which detailed a small trial conducted with 41 children, aged 8-12, who had specific learning difficulties (mainly dyslexia) who also showed ADHD features.  The children were given essential fatty acid supplements or a placebo for 12 weeks.  After 12 weeks cognitive (learning/mental) problems and behaviour problems were significantly lower for the group treated with fatty acids.  This small pilot study paved the way for further small studies which all indicate the importance of essential fatty acids in the management of behavioural problems(6,7,8,9).  Unfortunately large scale trials are still needed but funding is notoriously difficult to find for nutritional intervention trials (compared with drug trials). 

Dr Richardson wrote a review paper(10) detailing current thinking around essential fatty acids in childhood developmental and psychiatric disorders.  In it she details the fact that long chain omega-3 fatty acids (EPA and DHA) are often lacking in our diets and that evidence has built up to suggest that deficiencies and/or imbalances are associated with childhood developmental and psychiatric disorders including ADHD, dyslexia, dyspraxia, and autistic spectrum disorders.  The current evidence seems very supportive of dietary supplementation with these fatty acids, particularly EPA (eicosapentaenoic acid).  Dr Richardson stresses the need for large-scale studies to determine optimal treatment formulations and doses and the need to develop ways of identifying individuals most likely to benefit.  She points out “Childhood developmental and psychiatric disorders clearly reflect multifactorial influences, but the study of LC-PUFA [long chain polyunsaturated fatty acids] and their metabolism could offer important new approaches to their early identification and management”

Omega 3 fatty acid supplementation will not help all children affected by ADHD.  However, omega 3 fatty acids are beneficial to health for a number of reasons (which I frequently mention in my blog posts) and, as many of us do not consume oily fish regularly (at least twice per week as a minimum), supplementation seems prudent to make up for the dietary lack. 

A daily supplement providing around 300-500mg of EPA and 250mg of DHA may be worth trying.  The appropriate dose for the improvement of mood and cognition varies.  Some of the trials with ADHD used up to 1000mg EPA.  The quality of the supplement also needs consideration as fish oils may be contaminated with heavy metal residues e.g. mercury.  Supplements containing Vitamin E or C are worthwhile as these vitamins prevent the oil from oxidation (going rancid).  High dose fish liver oils are not recommended as these contain large amounts of vitamin D and A which can be toxic if taken in excess.   

There are many other nutritional factors (vitamins and minerals) associated with ADHD and related conditions and I hope to cover these important topics in time.  Any dietary interventions with children needs to be closely monitored and I would suggest speaking with your GP or health professional before embarking on a regimen.  Dietary interventions are to be viewed as complementary to any other management approaches.  Individual cases need individually tailored treatment. 

Please visit the Food For The Brain website for more ideas and information. 

(1)www.foodforthebrain.org
(2)Burgess JR et al.  2000.  Long-chain polyunsaturated fatty acids in children with attention deficit hyperactivity disorder.  American Journal of Clinical Nutrition.  71(1):327-330.
(3)Mitchell EA, et al.  1987.  Clinical characteristics and serum essential fatty acid levels in hyperactive children. Clin Pediatr.  26:406-411
(4)Stevens LJ et al.  1995.  Essential fatty acid metabolism in boys with attention-deficit hyperactivity disorder. Am J Clin Nutr.  62:761-768
(5)A. Richardson and B. Puri.  2002.  A randomized double-blind, placebo-controlled study of the effects of supplementation with highly unsaturated fatty acids on ADHD-related symptoms in children with specific learning difficulties.  Prog Neuropsychopharmacol Biol Psychiatry, Vol 26(2):233-9
(6)Colter AL et al.  2008.  Fatty acid status and behavioural symptoms of attention deficit hyperactivity disorder in adolescents: a case-control study. Nutr J.14;7:8.
(7)Johnson M et al.  2008.  Omega-3/Omega-6 Fatty Acids for Attention Deficit Hyperactivity Disorder: A Randomized Placebo-Controlled Trial in Children and Adolescents.  J Atten Disord.  Apr 30. [Epub ahead of print]
(8)Sinn N, Bryan J.  2007.  Effect of supplementation with polyunsaturated fatty acids and micronutrients on learning and behavior problems associated with child ADHD. J Dev Behav Pediatr.28(2):82-91.
(9)Effects of an open-label pilot study with high-dose EPA/DHA concentrates on plasma phospholipids and behavior in children with attention deficit hyperactivity disorder.
Sorgi PJ et al.  2007.  Nutr J. 13;6:16.
(10)Richardson AJ.  2004. Long-chain polyunsaturated fatty acids in childhood developmental and psychiatric disorders.  Lipids. 39(12):1215-22.

Written by Ani Kowal

On the 16th July I wrote about artichoke leaf extract (ALE) supplements for cholesterol lowering.  Evidence is also mounting for the usefulness of this plant supplement in the reduction of IBS symptoms (1,2).  In one study (2) 208 adults with IBS were given ALE for a two month period.  The individuals had a significant improvement whilst taking the supplement with a normalising of bowel pattern away from alternating constipation/diarrhoea toward normal.  The IBS sufferers also had a significant improvement in their total health-related quality of life scores.  The trials were small and provide preliminary evidence but it certainly seems that artichoke leaf extract is useful for an array of digestive complaints.  If you decide to try ALE supplements for the management of your IBS symptoms please follow the manufacturers dosage advice, taken in excess it may cause digestive upset.

When discussing IBS it is difficult not to mention the issue of food sensitivities or intolerances.  Some studies indicate that a large proportion of people afflicted with IBS have food sensitivities, very few have true food allergies, and that gas production and other IBS symptoms diminish when the sensitivities are discovered and the offending food(s) eliminated (3,4,5,6).  Assessing sensitivities can be quite subjective and therefore difficult to assess properly in a clinical-trial setting. 

Research suggests that some people with IBS may malabsorb the sugars lactose (found in milk), fructose (found in high concentrations in fruit juice and dried fruit) and sorbitol (found in diabetic and sugar-free products) (7).   Research shows that in a large majority of IBS patients with lactose malabsorption, a lactose-restricted diet can improve symptoms markedly both in the short term and the long term (8).  Fructose- and sorbitol-reduced diets in subjects with fructose malabsorption reduce gastrointestinal symptoms such as bloating, cramps, osmotic diarrhoea and other IBS symptoms (9).  Hence, individuals with IBS attempting to uncover food sensitivities should consider the possibility that milk, fruit juice, dried fruit and products containing sorbitol might cause worsening of their symptoms.

A note of caution – please do not attempt elimination diets without supervision from your GP or a fully qualified professional.  Many ‘food sensitivity tests’ are advertised at very high cost and, in my opinion, can often be unhelpful.  Working with a professional and keeping food diaries and symptom scores may uncover specific triggers for your personal symptoms.  Stress, emotions and psychology may also be playing a major role in your IBS symptoms so assessing how you feel could also prove helpful.  Foods may be triggering symptoms in conjunction with stressful/emotional periods but less-so at other times.

Finally I would like to briefly mention aloe vera juice.  Many individuals with digestive complaints report that their symptoms diminish greatly with the regular ingestion of an aloe vera juice drink or supplemental aloe capsules.  Most of the evidence so far is anecdotal (but that does not lessen personal experiences).  A few animal studies have started to provide weight to the evidence but very few human studies have occurred to date.  A test tube study(10) using human colon cells has shown that aloe vera did appear to work as a potent anti-inflammatory.  You may find it useful to try the juice yourself to see if it is helpful in reducing your personal symptoms.  Remember to follow the dosage guidance and try and keep note of your symptoms for about a week.  If the juice works for you then it is worth continuing with. 

That ends my posts on IBS, I do hope that the information presented over the last few days has been of help?!

(1)Walker AF et al.  2001.  Artichoke leaf extract reduces symptoms of irritable bowel syndrome in post-marketing surveillance study.  Phytotherapy Research.  15:58-61
(2)Bundy R et al.  Artichoke leaf extract reduces symptoms of irritable bowel syndrome and improves quality of life in otherwise healthy volunteers suffering from concomitant dyspepsia: a subset analysis.  J Altern Complement Med.  10:667-669
(3) King TS et al.  1998.  Abnormal colonic fermentation in irritable bowel syndrome.  Lancet.  352:1187-1189
(4) Jones AV et al.  1982.  Food intolerance: a major factor in the pathogenesis of irritable bowel syndrome.  Lancet.  ii:1115-1117
(5) Smith MA et al.  1985.  Food intolerance, atopy, and irritable bowel syndrome.  Lancet.  ii:1064
(6) Parker TJ et al.  1995.  Management of patients with food intolerance in irritable bowel syndrome: the development and use of an exclusion diet.  J Human Nutr Diet.  8:159-166
(7) Fernandez-Banares F et al.  1993.  Sugar malabsorption in functional bowel disease: clinical implications.  Am J Gastroenterol.  88:2044-2050.
(8) Bohmer CJ, Tuynman HA.  2001.  The effect of a lactose-restricted diet in patients with a positive lactose tolerance test, earlier diagnosed as irritable bowel syndrome: a 5-year follow-up study.  Eur J Gastroenterol Hepatol.  13(8):941-944
(9)Ledochowski M et al.  2000.  Fructose- and sorbitol-reduced diet improves mood and gastrointestinal disturbances in fructose malabsorbers.  Scand J Gastroenterol.  35(10):1048-52
(10)Langmead L et al.  2004.  Anti-inflammatory effects of aloe vera gel in human colorectal mucosa in vitro.  Aliment Pharmacol Ther.  19:521-527

Written by Ani Kowal

Both of the review studies(1,2) that I mentioned yesterday discuss the growing evidence that probiotics, supplemental beneficial bacteria, seem helpful in managing IBS.  Probiotics may help by reducing the level of inflammatory chemicals (cytokines), implicated in IBS.  Imbalances in gut bacteria can lead to chronic low-level inflammation in the intestines and the measurable presence of inflammatory markers in the bloodstream.   There are complications with the scientific studies that have taken place to date as it seems that the type of bacterial probiotic supplement used may be responsible for the degree of improvement noted in IBS sufferers.  Supplements containing Bifidobacteria seem to be especially effective.

(For definitions of probiotic, prebiotic and symbiotic please read Part I)

The problem with probiotic only supplements is the survival of the bacteria through our digestive system before they arrive at the large intestine.  It is often impossible to know how many, and which, live organisms are present in the supplements.  It is important to look for brands that are enteric-coated, so that the bacteria are not destroyed/digested by the stomach.  It is thought that probiotics work only as long as they are being taken, i.e. as the probiotic is no longer consumed, the added bacteria are rapidly washed out of the colon.  Hence prebiotic or a symbiotic supplements are probably the most beneficial in the long-term.  Another useful point to remember is that the bacteria are killed by heat so try not to take your probiotic supplement whilst drinking your morning cup of tea! 

Recently there have been some trials using symbiotics(3,4,5), supplements containing both probiotics and prebiotics, in the treatment of IBS and they have shown encouragingly positive results.  Two studies(3,4) found that the prebiotic-probiotic treatment significantly reduced feelings of general ill health, nausea, indigestion and flatulence.  Another study (5) found that a prebiotic-probiotic preparation was particularly helpful for sufferers of constipation-type IBS.  The supplement reduced general IBS symptoms, bloating and abdominal pain and increased stool frequency.

Larger trials are needed but a symbiotic supplement containing both probiotics and prebiotics may well be worth a try if you are suffering with the discomfort of IBS.  Look for supplements containing bifidobacteria and lactobacilli as these seem to be most beneficial.  After an initial period of a month or so you may wish to switch to a prebiotic (FOS) only supplement to maintain consistently high levels of gut friendly bacteria.  As I mentioned in an earlier post, I take a daily FOS supplement out of habit now and feel good on it!  Bacterial balance has been implicated in many conditions (not just those related to the digestive system) and may be important for keeping our immune system healthy.

Tomorrow I will be continuing the IBS theme so please check back for some more helpful ideas

(1)Wald A & Rakel D.  2008.  Behavioural and complementary approaches for the treatment of irritable bowel syndrome.  Nutrition in Clinical Practice.  23:284-292
(2)Heitkemper MM & Jarrett ME.  2008.  Update on irritable bowel syndrome and gender differences.  Nutrition in Clinical Practice.  23:275-283
(3)Bittner AC et al.  2005.  Prescript-Assist probiotic-prebiotic treatment for irritable bowel syndrome:a methodologically orientated, 2-week, randomized, placebo-controlled, double-blind clinical study.  Clin Ther.  27:755-761
(4)Bittner AC et al.  2007.  Prescript-Assist probiotic-prebiotic treatment for irritable bowel syndrome:an open-label, partially controlled, 1 year extension of a previously published controlled clinical trial.  Clin Ther.  29:1153-1160
(5)Colecchia A et al.  2006.  Effect of a symbiotic preparation on the clinical manifestations of irritable bowel syndrome, constipation-variant.  Results of an open, uncontrolled multicentre study.  Minerva Gastroenterol Dietol.  52:349-358

Written by Ani Kowal

Two review papers(1,2) have recently been published in the journal ‘Nutrition in Clinical Practice’ which look at the therapeutic approaches to dealing with irritable bowel syndrome (IBS).  They cover everything from cognitive behaviour therapy and hypnosis to diet and nutrition.  The papers are timely, this is a topic I am often asked about and have decided to spend the next few posts covering various nutritional aspects of IBS. 

IBS describes a combination of symptoms including constipation, diarrhoea, abdominal pain/discomfort, nausea and vomiting, feelings of fullness, gas and bloating.  Sufferers are often embarrassed by the condition which generally develops in individuals between the ages of 20 and 30 and affects around 20% of the population.  IBS also appears to be more common in women than men.

The causes of this uncomfortable condition are unclear.  However, an imbalance in intestinal bacteria is frequently implicated.  Often IBS develops after a bout of gasteroenteritis or repeat courses of antibiotics (which kill off the vast majority of intestinal bacteria).  The bacteria in the digestive system of individuals suffering from IBS seems to be different to healthy people with fewer ‘beneficial/friendly’ bacteria such as Bifidobacteria and Lactobacilli being present in those with IBS. 

Up to about 30 years ago it was a common misperception that the major functions of the large intestine (colon) was simply water re-absorption and storage of waste matter.  The colon is now recognised as an important organ due to the number of bacteria present (well over 10million bacteria are present in the colon per g of contents!).  These bacteria produce compounds, which can have beneficial/positive, neutral or damaging influences on the body.  Age, stress, antibiotics, the environment and diet can all affect the type of bacteria present in our digestive system.  A healthy diet may help boost the number of the friendly bacteria and hence decrease the incidence of infective disorders of the gastrointestinal tract and boost natural resistance against them.

The knowledge that specific species of bacteria may be of benefit to our health, especially Lactobacilli and Bifidobacteria, led to the development of probiotics, prebiotics and synbiotics which are designed to beneficially alter the bacteria present in our gut.  Most people will have a predominance of Bacteriodes bacteria in their digestive systems, these have both pathological and neutral effects.  For optimal health it would be better for us to have a gut dominated by Bifidobacteria and Lactobacilli.  The health promoting effects of these bacteria include prevention of the growth of harmful bacteria, improvement of immune functions, reducing gas/bloating problems, improved digestion and better absorption of essential nutrients and vitamin synthesis.  A probiotic, prebiotic or symbiotic supplement may be a way of beneficially altering the bacterial status of our colon. 

A probiotic is a supplement containing live friendly bacteria which aim to improve intestinal bacteria balance.  Probiotics are available as yoghurts, fermented milks, fortified fruit juices and freeze dried capsules/powders.   

A prebiotic is a food that stimulates the growth of the beneficial bacteria already present in the colon.  Fructooligosaccharides (FOS) which can be bought as powders are the most common prebiotics available.  Natural prebiotics can be found in asparagus, onion, chicory and garlic. 

Synbiotics are a mixture of probiotics and prebiotics. 

Tomorrow I will look further into these supplements and their use in the alleviation of IBS specific symptoms.

(1)Wald A & Rakel D.  2008.  Behavioural and complementary approaches for the treatment of irritable bowel syndrome.  Nutrition in Clinical Practice.  23:284-292
(2)Heitkemper MM & Jarrett ME.  2008.  Update on irritable bowel syndrome and gender differences.  Nutrition in Clinical Practice.  23:275-283

Written by Ani Kowal

Sticking to the theme of eye health I wanted to briefly write about cataracts today.  Cataracts are cloudy areas that develop in the lens of the eye, the cloudiness reduces the amount of light transmitted to the retina and this causes poor vision.  In the UK about 1 in 3 people over the age of 65 develop a cataract, which gradually forms over many years.  Initially vision may only be very mildly affected and this may not progress, however, in some individuals the vision will get worse over time. 

Treatment is an option when a cataract becomes bad enough to interfere with normal life e.g. if vision starts to interfere with reading, driving, watching TV etc or stops an individual from doing anything that they would normally do.  Before making a decision about treatment it is recommended to make sure your glasses are giving you maximum benefit.  Treatment involves the removal of the cloudy lens and replacement with an artificial plastic lens (an intraocular implant).

Cataracts seem to occur due to the breakdown and subsequent clumping of proteins in the lens.  Obviously, prevention is always better than cure!  Lifestyle factors that may increase the risk of cataract development include a poor diet low in antioxidant nutrients (found in fruits and vegetables), smoking and prolonged sunlight exposure.  Again, as with AMD, free radicals appear to play a causal role and hence dietary antioxidants may be protective.

I would like to highlight three (1,2,3) very recent research studies.  The first study(1) looked at the association between cataracts and dietary lutein and zeaxanthin, caroteinoids found in spinach, collard greens and kale.  The study involved 1802 women aged 50 to 79 years.  Women with high dietary levels of lutein and zeaxanthin had a 23% lower prevalence of cataract compared to those with low levels.  Women with the highest dietary intakes or highest blood serum levels of lutein and zeaxanthin as compared with those with the lowest were 32% less likely to have cataract.  For more information on these carotenoids and potential supplements please refer to Monday's post which looked at AMD.

The researchers involved in the second study(2) wanted to investigate the relationship between antioxidant nutrient intakes and incidence of age-related cataract over a 10 year period.  The study involved 2464 individuals (aged 49 or over at the start of the study) for 5-10 years.  Eye health was observed using lens photography and dietary intakes of various antioxidants, including zinc, beta carotene, vitamins A, C and E, was assessed.  Individuals with the highest total intake, from diet and supplements, of vitamin C had a 45% reduced risk of cataract.  An above average intake of combined antioxidants -vitamins C and E, beta-carotene, and zinc - was associated with a 49% reduced risk of cataract.  The authors of the study conclude that “Higher intakes of vitamin C or the combined intake of antioxidants had long-term protective associations against development of nuclear cataract in this older population”.

Both of these studies, as in the studies I highlighted in relation to eye health on Monday, re-iterate the importance of a diet rich in vegetables and fruits, which are fabulous sources of antioxidants.  As yet the role for supplementation in the prevention of cataract is unclear (and cannot, of course, substitute diet) but many individuals are taking multivitamin and mineral supplements to help keep their eyes, and bodies, healthy.  Future large supplementation trials are planned and I look forward to seeing the results.

The third study(3) involved around 2000 individuals aged 49 or over (at the start of a 5 year investigatory period).  The researchers found that higher dietary intakes of omega-3 polyunsaturated fatty acids were associated with a significantly reduced risk (42% compared to those with the lowest intakes) of developing cataract over 5 years.   For more information regarding omega 3 fatty acids and eye health please refer to the piece that I posted on Monday which looked at AMD.

(1)Moeller SM et al.  2008.  Associations between age-related nuclear cataract and lutein and zeaxanthin in the diet and serum in the carotenoids in the age related eye disease study, an ancillary study of the women’s health initiative.  Arch Opthalmol.  126:354-364
(2)Tan AG et al.  2008.  Antioxidant intake and the long-term incidence of age-related cataract: the blue mountains eye study.  Am J Clin Nutr.  87:1899-1905
(3)Townend BS et al.  2007.  Dietary macronutrient intake and five year incident cataract: the blue mountains eye study.  Am J Opthalmol.  143:932-939.

Written by Ani Kowal

My eyesight is something that I value very highly.  Without my spec's or contact lenses I have very limited vision.  Looking after my eyes, in order to prevent further long-sightedness in later life, is certainly high on my agenda.  Age Related Macular Degeneration (AMD) is the most common cause of blindness in people over the age of 50 in the UK and I feel that it deserves a little attention! 

The macular is the light sensitive area in the centre of the retina that controls visual field and the ability to see colours.  AMD is caused by the deterioration of the macular.  As this happens the peripheral, outer, vision remains intact as the centre field of vision becomes slowly blurry, grey or filled with a large black spot.  Two forms of AMD exists: the dry form which develops slowly, accounting for 90% of all cases; and the wet form which causes rapid deterioration of central vision.

The exact causes of AMD are unknown although free radical damage, where unstable oxygen molecules damage the eye cells, is strongly implicated.  Tobacco smoke and sun exposure can increase the level of free radicals in the body and both are a risk for AMD.  High blood pressure and diabetes are also risk factors as these conditions can limit blood flow to the eyes.

Evidence for diet and nutrition in the prevention, and to a certain extent treatment, of the condition is growing yearly.  The latest study was published in the August volume of the American Journal of Clinical Nutrition(1) and adds to the growing body of research(2,3,4,5,6,7,8) suggesting that oily fish and the long chain omega 3 fatty acids they provide, EPA and DHA (eicosapentaenoic acid and docosahexaenoic acid), may be preventative. 

This recent study(1) assessed the dietary intake data and photographic eye evidence of 105 individuals with AMD and compared it to 2170 control individuals (without any features of AMD).  All participants were aged 65 or over.  The researchers found that eating oily fish at least once per week compared with less than that was associated with a 50% reduced likelihood of having AMD.  There was no benefit from eating non-oily, white fish.  There was also a strong significant association between intake levels of DHA and EPA and AMD.  Individuals eating around 300mg or more of these fatty acids per day were 70% less likely to have AMD.  Two (75g) servings of oily fish, such as salmon, mackerel, sardines or trout, provides around 500mg of DHA and EPA 

The scientists are not yet recommending omega 3 supplements as the study did not investigate whether supplements would have the same benefit as dietary sources.  However, evidence for the potential benefits of fish oil (long chain omega 3 fatty acid) supplements is beginning to emerge, with one very recent study(5) finding that 800mg of DHA per day over 2-4 months was associated with beneficial changes in the macular. 

Omega 3 fatty acids are incredibly important for many aspects of health (and I have mentioned them throughout my blog postings).  Including at least two portions of oily fish per week is certainly recommended, however, many individuals in the UK do not achieve these intakes for various reasons.  A daily fish oil supplement providing around 250mg of EPA and 250mg DHA may be something worth considering (for general health).  For vegetarians and vegans a flaxseed oil supplement providing around 500-800mg of alpha-linolenic acid (a short chain omega 3 fatty acid which the body can convert to the longer chain forms) daily is a good way of ensuring a daily supply of these essential fats.

The other important nutrients worth discussing in relation to AMD prevention are the antioxidant carotenoids lutein and zeaxanthin, naturally found in foods such as spinach, collard greens and kale.  Research data(9,10,11,12) suggests that individuals with high dietary intakes of lutein and zeaxanthin, and high body levels of the carotenoids, have a reduced risk of developing AMD.  Supplements of these nutrients are now widely sold and targeted at eye health.  The supportive evidence for supplementation is not yet solid.  A small study(13) has shown benefit and paves the way for larger studies.  A very recent review(14) of the currently available evidence, published last month, concluded that “A definite association between lutein and zeaxanthin supplementation and clinical benefit has yet to be hown; however, it may still be an appropriate cautionary measure for patients at high risk for developing AMD”

Available ‘eye health’ supplements often contain vitamins C, E, beta carotene and the mineral zinc in addition to lutein and zeaxanthin.  The rationale behind this comes from dietary association studies and some research evidence.  If you are considering supplements remember that they are not a substitute (more of a bonus) for nutritious daily meals!  A healthy diet, rich in a variety of vegetables and fruits, will provide an array of antioxidant nutrients to keep the whole body healthy, including the eyes.

(1)Augood C et al.  2008.  Oily fish consumption, dietary docosahexaenoic acid and eicosapentaenoid acid intakes, and associations with neovascular age related macular degeneration.  American Journal of Clinical Nutrition.  88:398-406
(2)Chong EW et al.  2008.  Dietary omega-3 fatty acid and fish intake in the primary prevention of age-related macular degeneration: a systematic review and meta-analysis.  Arch Ophthalmol.  126:826-833.
(3)SanGiovanni JP et al.  2007.  The relationship of dietary lipid intake and age-related macular degeneration in a case-control study: AREDS Report No. 20.  Arch Opthalmol.  125:671-679
(4)Seddon JM et al.  2006.  Cigarette smoking, fish consumption, omega-3 fatty acid intake, and associations with age-related macular degeneration: the US Twin Study of Age-Related Macular Degeneration.  Arch Opthalmol.  124:995-1001
(5)Johnson EJ et al.  2008.  The influence of supplemental lutein and docosahexaenoic acid on serum, lipoproteins, and macular pigmentation.  Am J Clin Nutr.  87:1521-1529
(6)Cho E et al.  2001.  Prospective study of dietary fat and the risk of age-related macular degeneration.  Am J Clin Nutr.  73:209-218
(7)Seddon JM et al.  2001.  Dietary fat and risk for advanced age related macular degeneration.  Arch Opthalmol.  119:1191-1199
(8)Smith W et al.  2000.  Dietary fat and fish intake and age related maculopathy.  Arch Opthalmol.  112:222-227
(9)Seddon JM et al.  1994.  Dietary carotenoids, vitamin A, C and E and advanced age-related macular degeneration.  JAMA.  272:1413-1420
(10)Bone RA et al.  2000.  Lutein and zeaxanthin in the eyesm serum and diet of human subjects.  Experimental Eye Research.  71:239-245
(11)Bone RA et al.  2001.  Macular pigment in donor eyes with and without AMD:A case-control study.  Invest Opthalmol Vis Sci.  42:234-240
(12)Gale CR et al.  2003.  Lutein and zeaxanthin status and risk of age-related macular degeneration.  Invest Opthalmol Vis Sci.  44:2661-2465
(13)Richer S et al.  2004.  Double-masked, placebo-controlled, randomised trial of lutein and antioxidant supplementation in the intervention of atropic age related macular degeneration: the Veterans LAST study (Lutein Antioxidant Supplementation Trial).  Optometry.  75:216-230)
(14)Zhao L & Sweet BV.  2008.  Lutein and Zeaxanthin for macular degeneration.  Am J Health Syst Pharm.  65:1232-1238

Written by Ani Kowal