Vitamin D continues to hit the headlines, this time a study(1) finds an association between low vitamin D levels and increased risk of colorectal cancer.  Previously I wrote a detailed post regarding diet and lifestyle changes for colorectal cancer prevention which is certainly worth looking at in conjunction with this information.

The authors of the current study (1) wanted to examine the circulating blood vitamin D concentrations, dietary intakes of vitamin D and calcium, and the risk of colorectal cancer in European concentrations.  The researchers used data from more than 520,000 individuals, from these 1248 individuals with colorectal cancer (which developed after enrolment into the study), were compared/matched to 1248 control participants (without colorectal cancer). 

Low circulating vitamin D concentrations were linked to an increased risk of colorectal cancer and high circulating citamin D concentrations were linked to a reduced risk of colorectal cancer (1).  Analysis of data found that individuals with the highest circulating vitamin D concentrations had a 40% lower risk of colorectal cancer than those with the lowest levels.  Greater dietary intake of calcium was also associated with a lower colorectal cancer risk. 

This study only shows an association between low vitamin D levels and increased risk of colorectal cancer, no definitive conclusions can be drawn about whether low levels ‘cause’ cancer or not.  The authors of the study conclude that further randomised controlled trials are needed to assess whether increasing the circulating levels of vitamin D, through supplementation, can effectively decrease the risk of colorectal cancer (1).

In a press release (2) it was noted that some recent study publications have suggested maintenance of blood vitamin D levels at 50 nmol/l or higher are needed for colorectal cancer prevention (some doctors have recently been suggesting that blood levels of vitamin D of at least 40nmol/l are needed for optimal health).   The study, mentioned above, found that blood levels below the 50nmol/l mark were associated with an increase risk but that levels of vitamin D above the 75 nmol/l were not associated with any additional reduction in colon cancer risk. 

As mentioned in my previous posts on Vitamin D, frustratingly there is no consensus about the amount of daily vitamin D intake necessary to maintain blood levels at around 40-50nmol/l.  In the UK it is known that most people have low blood vitamin D levels. I would suggest most individuals in the UK would require a supplement of around 2000iu vitamin D daily.  Higher doses may be useful but I would not recommend such a regimen unless under the supervision of a medical doctor who can monitor blood levels regularly.

Of course, when it comes to colorectal cancer there are numerous other links between diet, lifestyle and risk – please read my previous post on the topic for more information. 

(1) Jenab et al.  2010.  Association between pre-diagnostic circulating vitamin D concentration and risk of colorectal cancer in European populations:a nested case-control study. BMJ.  340: b5500 DOI: 10.1136/bmj.b5500
(2)press release: BMJ-British Medical Journal (2010, January 22). High vitamin D levels linked to lower risk of colon cancer. ScienceDaily. Retrieved January 22, 2010, from http://www.sciencedaily.com/releases/2010/01/100122002340.htm
Written by Ani Kowal

This week is national Food allergy and Intolerance week - for more information about this campaign week please visit the Allergy UK website.  “Allergy UK is a national medical charity established to represent the views and needs of people with allergy, food intolerance and chemical sensitivity”
 

Allergy UK say: “Too often allergy or intolerance sufferers become labeled as being fussy eaters or just thought to be following the latest fad, this could not be further from the truth. Stolen Lives 7 - Food Allergy and Intolerance Report (available at the Allergy UK website), by Allergy UK highlights how difficult it is to live with a food allergy and intolerance. The most simple of choices such as what to make for dinner or what to put in their child's packed lunch becomes a nightmare”.

It can be really challenging to decipher whether abdominal/gut or other irritating symptoms are due to stress, illness or a food intolerance or allergy.  Often medical doctors disregard the idea of intolerances but as mentioned above the symptoms can be very distressing, and certainly very real, to the sufferer.  Allergy UK say: “Finding out what you are intolerant to is the another priority for many. The lack of understanding regarding food intolerance within the medical profession leads many to search for a reliable test to identify the cause of their problems. A staggering 88% of respondents reported that they had suffered for years before they found help in managing their food intolerance with little or no help from their GP. Thankfully a new food intolerance testing kit, which detects foods specific IgG antibodies, Food Detective™ has been launched by Cambridge Nutritional Sciences Ltd. Food Detective™ is reliable and simple to use at home”.  The Food Detective kit is widely available and can be purchased here.

If you decide to use the Food Detective test kit I would urge you to see a registered Nutritionist or Nutritional practitioner, or indeed a sympathetic GP, to go over the results with you.  It is never a good idea to simply cut out whole food groups as this can lead to nutritional deficiencies and other problems. 

There are two websites I would recommend where you can search for registered practitioners in your area:
1)      The UK voluntary resister of nutritionists
2)      The British association for applied nutrition and nutritional therapy

For more information about what food allergies and intolerances are and what causes them visit the allergy UK website

The most common symptoms of an allergy or intolerance are:
*Sneezing 
*Runny nose
*Itchy eyes and ears
*Severe wheezing, coughing, shortness of breath
*Sinus problems
*Sore palate
*Nettle-like rash.

Symptoms of intolerances and allergy can be eased with nutritional and dietary help.  For more information on this I would suggest you read the two posts that I wrote about asthma (Part 1. Part 2.) and also my posts regarding hay fever.  Some general advice would be to boost the immune system via a diet rich in a variety of vegetables and fruits which provide vitamins and bioflavonoids.  In addition to this omega 3 fatty acids from oily fish e.g. salmon, trout, mackerel and sardines (at least two portions per week) are really helpful to the immune system and also to reduce inflammation in the body.  Probiotics have also been found to be useful for allergy prevention, symptom easing and for boosting immune health.  I have discussed these points further in the posts mentioned above.  Taking an omega 3 fatty acid supplement may be incredibly useful to ease allergic symptoms.  Many people in the UK do not get enough of these essential fats in their diet.  A supplement providing about 250-350mg EPA and 250-350mg DHA daily could be considered.  For vegetarians and vegans a flaxseed oil supplement containing around 500-1000mg alpha linoleic acid daily is an option, vegetarian EPA and DHA supplements made from algae are becoming more available to buy and provide a good choice. 

Written by Ani Kowal

Vitamin D and calcium are important for bone health.  With regards supplementation with these nutrients to prevent fracture the research to date has often been conflicting and inconclusive.  However, very recent evidence published in the British Medical Journal (1) has found that supplementation with both of these nutrients together is effective in fracture prevention.

The authors of the study conclude “This individual patient data analysis indicates that vitamin D given alone in doses of 10-20 µg is not effective in preventing fractures. By contrast, calcium and vitamin D given together reduce hip fractures and total fractures, and probably vertebral fractures, irrespective of age, sex, or previous fractures”.  The research (1) looked at data from seven major randomised trials with a total of 68,517 participants (men and women aged between 47 and 107 years old).

In a press release (2) professor John Robbins, one of the study authors said: "What is important about this very large study is that goes a long way toward resolving conflicting evidence about the role of vitamin D, either alone or in combination with calcium, in reducing fractures," "Our WHI research in Sacramento included more than 1,000 healthy, postmenopausal women and concluded that taking calcium and vitamin D together helped them preserve bone health and prevent fractures. This latest analysis, because it incorporates so many more people, really confirms our earlier conclusions."

Fractures are a major cause of disability, loss of independence and death for older people -  fractures can often be the result of osteoporosis, a disease characterized by low bone mass and bone fragility.  Professor Robbins says (2) "This study supports a growing consensus that combined calcium and vitamin D is more effective than vitamin D alone in reducing a variety of fractures," "Interestingly, this combination of supplements benefits both women and men of all ages, which is not something we fully expected to find. We now need to investigate the best dosage, duration and optimal way for people to take it."

In an editorial (3), written about this recent research, in the British Medical journal Dr Sahota writes about the implications of the current evidence in clinical practice saying: “Although the evidence is still confusing, there is growing consensus that combined calcium and vitamin D is more effective than vitamin D alone in reducing [non-vertebral] fractures. Higher doses are probably necessary in people who are more deficient in vitamin D, and treatment is probably more effective in those who maintain long term compliance. Further studies are needed to define the optimal dose, duration, route of administration, and dose of the calcium combination”. 

As mentioned in many of my previous posts on vitamin D, most of the UK population are probably suffering from insufficient or deficient vitamin D levels. 

Fragility fractures cause excess mortality, substantial morbidity, and related health and social issues and financial problems in older people.  Risk of fracture is higher in institutionalised older people than in community dwelling older people of the same age. This reflects a greater risk of falls and lower bone mineral density in these populations.  Vitamin D insufficiency and deficiency is common in older people, particularly in residential and care homes.

The current study (1) suggests that “Daily calcium and vitamin D supplementation, even at doses as low as 10 µg of vitamin D daily, significantly reduces the risk of fracture”  the effective dose of supplements in the study was 1000mg calcium + 20micrograms vitamin D (the equivalent of 800iu).  Recent work with vitamin D suggests that up to 5000iu daily for adults may be required to keep blood levels of vitamin D optimal.  I would suggest most individuals in the UK would require around 2000iu vitamin D daily.  Higher doses may be useful but I would not recommend such a regimen unless under the supervision of a medical doctor who can monitor blood levels.

(1)The DIPART (vitamin D Individual Patient Analysis of Randomized Trials) Group.  2010.   Patient level pooled analysis of 68 500 patients from seven major vitamin D fracture trials in US and Europe.  BMJ.  340:b5463 doi:10.1136/bmj.b5463
(2)Press release: University of California - Davis - Health System (2010, January 15). Benefits of calcium and vitamin D in preventing fractures confirmed. ScienceDaily. Retrieved January 15, 2010, from http://www.sciencedaily.com/releases/2010/01/100114143325.htm
(3) Sahota O.  2010.  Reducing the risk of fractures with calcium and vitamin D.  BMJ.  340:b5492

Written by Ani Kowal

The herb thyme has recently (1) been found to suppress a specific enzyme (promotes specific biochemical reactions in the body), called Cyclooxygenase-2 (COX-2), which plays a key role in inflammation.  The researchers involved in this laboratory-based cell study found that a specific chemical found in thyme, called carvacrol, seemed primarily responsible for the inflammation suppressing activity.  Other botanical essential oils were also studied – clove, rose,e ucalyptus, fennel and bergamot – these also exhibited inflammation suppressing properties but to a lesser degree when compared to thyme, which reduced COX-2 levels by almost 75%.

Plant essential oils have been used for many years in various remedies but the way they work has not been clearly understood.  The authors of this study suggest that further understanding of the anti-inflammatory properties of various plant essential oils, or their specific components like carvacrol could be very important for future formulation of anti-inflammatory medications and remedies.

There have been a few small studies (2,3,4) using extracts of the herb thyme which have found that it may be helpful for treating the symptoms of bronchitis and coughs.  This could be due to the anti-inflammatory properties as mentioned above and also the antioxidant properties of thyme which have been demonstrated recently in cell studies (e.g.5,6).

Thyme, as well as a variety of other herbs, is now added to herbal antioxidant supplement preparations and can also be purchased as a ‘tea’ and an oil.  Further studies with the herb need to take place before any firm conclusions can be drawn and recommendations made for its use.  However, if you have a cough you may want to look out for herbal cough remedies that contain thyme or perhaps try burning a little of the oil in an oil burner, or sipping on some thyme tea to see if it brings relief to your symptoms. 

In the future I expect that more herbal preparations will be investigated and incorporated into medicines for various uses.  The antioxidant and anti-inflammatory properties of thyme and other herbs is interesting and exciting since many common health complaints are linked to inflammation and ‘oxidative stress’.

(1)Hotta M et al.  2010.  Carvacrol, a component of thyme oil, activates PPAR  and  and suppresses COX-2 expression.  Journal of Lipid Research.   51: 132-139
(2) Kemmerich B.  2007. Evaluation of efficacy and tolerability of a fixed combination of dry extracts of thyme herb and primrose root in adults suffering from acute bronchitis with productive cough. A prospective, double-blind, placebo-controlled multicentre clinical trial. Arzneimittelforschung.  57(9):607-15
(3) Kemmerich B et al.  2006.   Efficacy and tolerability of a fluid extract combination of thyme herb and ivy leaves and matched placebo in adults suffering from acute bronchitis with productive cough. A prospective, double-blind, placebo-controlled clinical trial. Arzneimittelforschung.  56(9):652-60
(4) Büechi S et al.  2005.  Open trial to assess aspects of safety and efficacy of a combined herbal cough syrup with ivy and thyme. Forsch Komplementarmed Klass Naturheilkd.  12(6):328-32.
(5) Rana P & Soni G.  2008.  Antioxidant potential of thyme extract: alleviation of N-nitrosodiethylamine-induced oxidative stress.  Hum Exp Toxicol. 27(3):215-21.
(6) Wang HF et al.  2008.  DPPH free-radical scavenging ability, total phenolic content, and chemical composition analysis of forty-five kinds of essential oils.  J Cosmet Sci.  59(6):509-22.
Written by Ani Kowal

Selenium isn’t a mineral that receives a lot of press attention, however it is an essential trace element that is incredibly vital to our health.  I first became aware of the importance of selenium for optimal health when I was studying for my MSc in Nutritional Medicine at the University of Surrey.  My professor at that time, Margaret Rayman, was (and is) a leading scientific researcher in the field of selenium.  At the time I was studying (2000-2002) there was a lot of research linking low selenium intakes to increased prostate cancer risk in men.  A very recently published paper (1) has now found that low selenium intakes seem to be tied to throat and stomach cancers too.  This is a preliminary study and further research is certainly required before any firm conclusions can be drawn.

Selenium acts as an important antioxidant in the body and this may account for part of the role it plays in cancer prevention.  As an antioxidant selenium may also be useful in preventing conditions related to inflammation such as pancreatitis, rheumatoid arthritis, systemic inflammatory response syndrome, asthma and cardiovascular disease, to name but a few.  It is also vital for a healthy immune system and plays a role in fertility in men and women.  In men it is vital for good sperm motility and in women selenium appears to be vital in very early pregnancy (2)

With regards the potential cancer protective role of selenium the antioxidant role may not be the only way that selenium acts.  Selenium also seems to act at the DNA level on specific genes in a variety of complicated ways (2)

As well as the requirement of selenium for antioxidant defence there is evidence that selenium:
* Is needed for thyroid function
* Is required by the immune system
* Has important antiviral effects
* Is needed for reproduction
* Enhances mood
* Reduces the risk of cancer
* Protects against mercury toxicity

The effect of selenium and its importance is most observable in populations where selenium status is low. The amount of selenium in the soil where food is grown determines its selenium content.  This is important here in the UK since our soils are very low in selenium.  The UK RNI (reference nutrient intake) for selenium is 75mcg/d for adult men and 60mcg/d for adult women.  However in the UK selenium intakes are estimated to be 39mcg/d which is very low and probably inadequate for most individuals (3).  Selenium intakes in the UK have fallen over the last 25 years largely due to the decrease in imports of high selenium wheat from the USA and Canada.  Plant foods are generally low in selenium in the UK/Europe where soil selenium levels are low (2).

Care is needed with supplementation since high doses of selenium can build up in the body and are toxic to health.  I would suggest not taking more that 100mcg/d.  I also do not recommend taking selenium as a single nutrient supplement since nutrients interact in complex and synergistic ways.  If you are taking a multi-vitamin and mineral supplement check to see that it contains selenium, if not then consider switching to a multi-formulation that does contain selenium.  Unfortunately dietary sources of selenium are few in the UK.  Brazil nuts (just 4-6 a day) and fish contain the highest concentrations in the diet of the UK population.  Some selenium rich flours are available to buy for cooking with

(1)Steevens J et al.  2009.  Selenium status and the risk of esophageal and gastric cancer subtypes: the Netherlands cohort study.  Accepted Manuscript, 14 December 2009.  Gastroenterology.  DOI: 10.1053/j.gastro.2009.12.004
(2) Rayman, M.P. 2000.  The importance of selenium to human health.  The Lancet 356: 233-241.
(3) BNF (British Nutrition Foundation).  2001.  Briefing Paper: Selenium and Health.

Written by Ani Kowal

Folic acid is gaining quite a lot of attention, in 2009 I mentioned it with regards the prevention of birth defects, prevention of premature births, low birth weights and also ADHD.  Recently a study (1) has also found that folic acid use pre-pregnancy and in early pregnancy is associated with a reduced risk of congenital heart defects (heart abnormality present from birth) in newborns.

The study scientists(1) looked at over 600 mothers who had delivered infants with heart defects (but without any genetic or related abnormalities).  These were compared to a ‘control’ group.  Folic acid use was associated with a reduced risk of congenital heart disease in infants  “Use of periconceptional folic acid supplements (of at least 400micrograms a day) was related to approximately 20% reduction in the prevalence of any CHD. Given the relatively high prevalence of CHD worldwide, our findings are important for public health” (1)

The authors note that the findings could be very significant since heart related birth defects can be quite common occurring in up to 2 newborns in every 100 worldwide.  When results were further broken down to look at specific heart defects it was found that women taking folic acid supplements had almost a 40% lower risk of having a child with a heart defect involving the septum, a part of the heart which separates one side of the heart from the other, compared to that of the general population (1).  This is a preliminary study but certainly deserves attention.  Further research would be necessary before any firm conclusions could be drawn

Folic acid supplements have long been recommended for all pregnant women, women planning on becoming pregnant and also women of childbearing age.  The reason for this recommendation is that folic acid is crucial for optimal foetal development very early in pregnancy, at a time when many women do not realise they are even pregnant.  At this early stage this nutrient of the B-vitamin group is known to prevent neural tube (brain and spinal cord) birth defects such as spina bifida.

If you are planning pregnancy or a woman of childbearing age who could fall pregnant it is certainly worth taking a multi-nutrient supplement which contains folic acid.  Specific supplements are available for pregnant women and those planning pregnancy and it is always a good idea to check with your doctor or midwife before starting supplementation.

Foods particularly rich in folate include leafy vegetables such as spinach, asparagus, turnip greens, lettuces, dried or fresh beans and peas, fortified cereal products, sunflower seeds, yeast extract, liver and liver products.

(1) van Beynum IM et al.  2009.  Protective effect of periconceptional folic acid supplements on the risk of congenital heart defects: a registry-based case-control study in the northern Netherlands. Eur Heart J. [Epub ahead of print]
Written by Ani kowal

Following on from my previous posts on premenstrual syndrome (PMS) I wanted to discuss the herb vitex agnus castus and how this supplement may also be useful to women suffering from PMS.  Previously I have mentioned this herb in relation to breast pain in women

The herb, vitex Agnus Castus, also known as chasteberry, grows in subtropical climates throughout the world.  Traditionally it has been used in the treatment of many ‘female ills’.  The herb itself does not contain any hormones, or hormone-like substances but it does appear to have an effect on part of the brain known as the pituitary gland which controls the production of the hormone progesterone from the ovaries.  It also appears to stop the excessive production of a hormone called prolactin which usually regulates breast-milk production but also has other, lesser-known, actions.  Prolactin is thought by some scientists to be responsible for certain PMS symptoms.  Vitex also contains the flavonoids casticin and isovitexin and it is thought that these flavonoids may help reduce the symptoms of fluid retention in PMS since flavonoids appear to facilitate repair of damage responsible for small blood vessel permeability which lead to fluid retention.

Many practitioners find that vitex agnus castus is incredibly useful in the treatment of PMS and there are many published research papers which back up their practical experiences.  Early studies (1,2,3) indicate that vitex is useful in the treatment of PMS symptoms.  One of these studies (3) published in the British Journal of Medicine concluded that “Dry extract of agnus castus fruit is an effective and well tolerated treatment for the relief of symptoms of the premenstrual syndrome”.  Symptoms that were aided with vitex agnus castus included: irritability, mood alteration, anger, headache, breast fullness and bloating.  Studies tended to run for at least 3 menstrual cycles.

A paper published this year (4) looked at the efficacy of vitex agnus castus compared to placebo treatment for PMS in over 200 women for three menstrual cycles.  The results show that the herb was safe, well tolerated and effective in the treatment of moderate to severe PMS.  Another interesting study published this year (5) found that agnus castus in combination with St.John’s Wort was effective in treating PMS-like symptoms among women starting to go through the menopause (perimenopausal women).

If you suffer from PMS on a regular monthly basis it may well be worth trying a vitex agnus castus supplement to see if it is useful for you.  The herb is commonly available as drops, tablets and capsules and most practitioners recommend that it is taken first thing in the morning upon waking up.  It may take a while before a significant benefit is seen and often it is recommended that supplements be taken for at least four menstrual cycles to determine whether or not they are proving useful to the individual woman.  The strength of supplement varies from manufacturer to manufacturer so always check the dosage instructions and adhere to those.

1.Berger D et al.  2000.  Efficacy of Vitex agnus castus L. extract Ze 440 in patients with pre-menstrual syndrome (PMS). Arch Gynecol Obstet. 264(3):150-3.
2.Loch EG et al.  2000.  Treatment of premenstrual syndrome with a phytopharmaceutical formulation containing Vitex agnus castus. J Womens Health Gend Based Med. 9(3):315-20.
3.Schellenberg R.  2001.  Treatment for the premenstrual syndrome with agnus castus fruit extract: prospective, randomized, placebo controlled study.  BMJ.  322:134-137. 
4. He Z et al.  2009.  Treatment for premenstrual syndrome with Vitex agnus castus: A prospective, randomized, multi-center placebo controlled study in China. Maturitas. 63(1):99-103
5. van Die MD et al.  2009.  Effects of a combination of Hypericum perforatum and Vitex agnus-castus on PMS-like symptoms in late-perimenopausal women: findings from a subpopulation analysis. J Altern Complement Med. 15(9):1045-8.
Written by Ani Kowal

Back in August I wrote about how diet can impact the brain and behaviour in children.  Nutrition for the brain is something I am very interested in and those of you who follow this blog will see that there is a lot of scientific evidence to show that what we eat can make a difference to mood and feelings as well as brain structure and function.

A very recent review study (1) has concluded that multi-nutrient supplementation may be associated with a small but significant increase in a measure of intelligence and academic performance in healthy schoolchildren.  The authors of the study do state however that “more research is required, however, before public health recommendations can be given” (1).

The researchers undertook the study because “Although multiple micronutrient interventions have been shown to benefit children's intellectual development, a thorough evaluation of the totality of evidence is currently lacking to direct public health policy” (1).  The aim of the research was to review the present literature on the effects of multiple-nutrient supplements on cognitive (mental/intellectual) performance in school aged children (children aged up to 18).  The researchers looked at data from trials published between 1970 and 2008 – quite a huge body of work!  As stated above, they found that multi-nutrient supplements seemed to have a small but significant positive effect on academic performance. 

The important aspect of these kinds of research studies, in my opinion, is that they show that nutrition does impact the brain, thinking, mood and therefore perhaps academic performance.  Limitations of such studies include the quality of the supplement, the quantity and also the actual diet of the child.  If you read the post from August you will see that overall diet quality is very important to the brain.  A good supply of daily vegetables, fruits, unrefined and unprocessed foods and healthy omega 3 fats as well as a protein supply with each meal is a great way to look after body and mind.  Regular exercise is also crucial for mood. 

In terms of supplements, they can never replace a healthy diet.  If you are considering supplements I would suggest a good quality multivitamin-mineral supplement, I like food-state supplements as they are made from ‘food’ and not chemicals and are easily absorbed into the body.  In addition to this I think that a daily omega 3 fatty acid supplement is definitely worth considering – these fats really are essential for the brain.  The most effective of the omega 3 fatty acids for brain function seem to be the long chain omega 3 fats EPA and DHA which are found in oily fish such as salmon, trout, mackerel and sardines.  These can be purchased as an oil or in capsule form.  Many of the oils are made easy for children to take as they are flavoured and have no fishy taste or smell.  For vegetarians and vegans flaxseed oil can be taken – this is a shorter chain omega 3 fat and not as effective, since the body has to work hard to convert it into the longer chain structure – however, it is certainly worth taking.  This kind of fat can be found in good amounts in walnuts and flaxseeds.  Vegan EPA and DHA is now being produced from algae, it is expensive but available to buy from some retailers and online.

(1)Eilander A et al.  2010.  Multiple micronutrient supplementation for improving cognitive performance in children: systematic review of randomized controlled trials.  American Journal of Clinical Nutrition.  91: 115-130
Written by Ani Kowal