It seems like an odd link, diet and breathing, but actually it makes enormous amounts of sense.  Our bodies need nutrients to function effectively.  Nutrition affects every cell from those that make up our bones to those of the skin.  The lungs and the cells of the immune system, both of which are involved in asthma, are no exception.  During an asthma attack the immune system produces certain antibodies (immunoglobulin E) and these stimulate the release of a chemical called histamine in the lining of the airways in the lungs.  The airways consequently become inflamed and swollen, excess mucous is also released and this can block the smaller airways and affect breathing.

The asthma statistics(1) for the UK are shocking.  5.2 million of us are currently receiving treatment for the condition.  1.1 million sufferers are children, that represents 1 in 10 kids, and 4.1 million are adults, that is 1 in 12.  On average there will be 3 children in every classroom who have asthma in the UK.  We also have the highest prevalence of severe wheeze in children aged 13-14 years WORLDWIDE!  Not a position to be proud of.  Every 19minutes a child is admitted to hospital due to their asthma and asthma costs the NHS over £996million per year.  Employers ought to care too as over 12.7million working days are lost to asthma each year.

I am an optimist, so this post is not all doom and gloom!  Dietary change can make a terrific difference!

The decision to write about asthma was prompted by two reasons.  The first was watching a child come out of a fast-food outlet and immediately using his “puffer” medication and the second was that two very interesting studies(2,3) have been published this month which link the adherence to a Mediterranean diet to a reduction in asthma symptoms.

In the first study(2) the scientists looked at the diet of 1784 children who were aged around 4 years, they found that adhering to a traditional Mediterranean diet was a protective factor for wheezing.  The second study(3) looked at diet during pregnancy and what affect that had on children when they were 6 years old.  The results indicate a protective effect of adherence to a Mediterranean diet during pregnancy against asthma-like symptoms (including wheezing and allergy) in childhood.  The lead scientist of the second study, Dr Chatzi, has previously published studies which indicate the protective effects of a Mediterranean diet against asthma symptoms.

So what constitutes a traditional Mediterranean diet?  Basically, this is healthy diet rich in a variety of different fruits and vegetables, legumes (peas and beans), oily fish, nuts and seeds, olive oil and unrefined wholegrains.  The diet is also high in fibre and relatively low in red meat, saturated fats and trans fatty acids (which are abundant in some processed foods).  The total fat content in general is relatively high but the type of fat is monounsaturated and also high in omega 3 fatty acids.  There are many reasons why this kind of healthy balanced diet could reduce the prevalence of asthma symptoms:

Fruits and vegetables are abundantly rich in all sorts of vitamins and flavonoids (a group of over 4000 plant compounds).  Studies (7,8) have shown that the flavonoid quercetin (found abundantly in onions and apples) appears to reduce the risk and severity of asthma symptoms.  This is probably due to the anti-inflammatory properties that quercetin exhibits in the body.  Vitamin C may be particularly important to asthmatics (9) as it seems to reduce the degree of constriction in the airways.  Studies (10) have found that asthma sufferers tend to have lower plasma vitamin C levels than non-asthmatics and supplementation of 1000mg Vitamin C a day may help improve lung function and reduce the frequency and severity of asthma attacks.  As mentioned in the post on hayfever, Vitamin C and Quercetin both act as natural anti-histamines in the body.  Asthmatics tend to have high histamine levels.  Histamine is produced by cells of the immune system and stimulates an inflammatory reaction in the body which may be responsible for the wheezing and shortness of breath in asthma sufferers.

Other vitamins and nutrients found in fruits and vegetables, such as carotenes, have also been implicated as important for prevention of symptoms in asthma sufferers.

Nuts, Seeds and Wholegrains are rich in the mineral magnesium.  A diet high in magnesium may well be useful for asthmatics since this important mineral appears to alleviate the bronchoconstriction (tightening of the airways in the lungs) associated with asthma.  There are many studies (far too many for me to list) which indicate the importance of magnesium in those suffering with asthma.  A study in children showed that low magnesium intakes are associated with poorer lung function(4) another found that asthma patients supplemented with 400 mg magnesium a day showed an improvement in asthma symptom scores(5).  Many studies have also found that asthmatics commonly have lower levels of magnesium in their blood(e.g. 6).  The National Diet and Nutrition Surveys (NDNS) for the UK have found that dietary intakes of magnesium are generally low in most children and women in the UK.  We would all do well to try and include more nuts, seeds and wholegrains into our daily diets. 

Fat:  There is some evidence that asthma may be related to an imbalance in fatty acids in the diet.  An Australian study(11) found that a diet high in omega 6 fatty acids and low in omega 3 fatty acids increased the risk of asthma symptoms in a large group of children.  Excessive amounts of omega-6 fatty acids, found in vegetable oils, and a relative lack of omega-3 fats, found in oily fish such as salmon and mackerel and some nuts and seeds, seems to promote inflammation and aggravate asthma. Inflammatory chemicals produced from omega 6 fats by the immune system can trigger constriction of the airways and mucous production.  Omega 3 fatty acids are involved in the production of anti-inflammatory chemicals by the cells of the immune system. 

One study(12) in asthmatic patients found that supplementation with corn oil (rich in omega-6 fats) tended to increase the production of inflammatory white blood cells, whereas supplementation with perilla seed oil (rich in omega-3 fats) had the opposite effect.  Patients treated with perilla seed oil also had significant increases in their lung function.  In another study(13), supplementation with fish oil (rich in the omega 3-fats) for 10 months reduced asthma symptom scores in a group of children.  Avoidance of excessive amounts of margarine and vegetable oils, and the inclusion of oily fish such as salmon, trout, mackerel and herring (or flaxseed oil for vegetarians) in the diet may, therefore, possibly help to control asthma symptoms.  Using olive oil in place of vegetable oils will probably prove useful as it is a monounsaturated fat and does not contribute to inflammation in the body, indeed it may even play a role in reducing inflammation(14).

In part II I will be covering other important dietary measures that affect asthmatics

(1) Asthma UK www.asthma.org.uk
(2) Castro-Rodriguez JA et al.  2008.  Mediterranean diet as a protective factor for wheezing in preschool children.  J Pediatr.  152(6):823-8, 828
(3) Chatzi L et al.  2008Mediterranean diet in pregnancy is protective for wheeze and atopy in childhood. Thorax.  63(6):507-13
(4) Gilliland FD et al.  2002.  Dietary magnesium, potassium, sodium and children’s lung function.  Am J Epidemiol.  155(2):125-131
(5) Hill J et al.  1997.  Investigation of the effect of short-term change in dietary magnesium intake in asthma.  Eur Respir J.  Oct;10(10):2225-9.
(6) Alamoudi OS.  2000.  Hypomagnesemia in chronic, stable asthmatics: prevalence, correlation with severity and hospitalization.  Eur Resoir J.  16:427-431
(7) Knekt P et al.  2002.  Flavonoid intake and risk of chronic diseases.  Am J Clin Nutr.  76:560-568.
(8) Saheen SO et al.  2001.  Dietary antioxidants and asthma in adults: population-based case-control study.  Am J Respir Crit Care Med.  164:1823-1828
(9) Bielory L et al.  1994.  Asthma and Vitamin C.  Annals Allergy.  73(2):89-96.
(10) Harik-Khan RI et al.  2004.  Serum vitamin levels and the risk of asthma in children.  Am J Epidemiol.  159:351-357.
(11) Oddy WH et al. 2004. Ratio of omega-6 to omega-3 fatty acids and childhood asthma.  Journal of Asthma.  41:319-326.
(12) Okamoto, M et al.  2000.  Effects of dietary supplementation with n-3 fatty acids compared with n-6 fatty acids on bronchial asthma.  Intern Med.  39(2):107-111
(13) Nagakura et al.  2000.  Dietary supplementation with fish oil rich in omega-3 polyunsaturated fatty acids in children with bronchial asthma.  Eur Resp J.  16(5):861-865.
(14) Beauchamp GK et al.  2005.  Phytochemistry: ibuprofen-like activity in extra-virgin olive oil.  Nature.  437:45-46.

Written by Ani Kowal

As I was tucking into my lunch yesterday I was taken by just how tasty the chickpeas were!  Munching on the little gems got me thinking about their nutritional value and their potential benefits to our health.

These ‘legumes’ go by many names: Chickpea, Ceci Bean, Indian Pea, Egyptian Pea, Garbanzo Bean and Gram and are mainly grown in the Mediterranean, Indian subcontinent and western Asia where they form a major part of the diet.  I was interested to learn that they are thought to be one of the earliest vegetables cultivated by humans.

Chickpeas are a useful source of fibre, zinc, folate and protein.  Being ever curious I hit the medical journals to see if there were any chickpea-specific studies.  I was in luck, one small study(1) has been published this month.  The authors wanted to assess the impact that incorporating chickpeas into the diet of 45 adults would have on their health.  The individuals taking part consumed about 728g of canned, drained chickpeas per week, (if you break this down to 100g per day it doesn’t sound like such a huge amount!), for 12 weeks.  After this time the participants went back to eating their normal diet for 4 weeks. 

In the ‘chickpea phase’ they ate around 7g more fibre a day (this is significant, as the UK population generally do not consume enough fibre) than they did during the ‘normal phase’.  They also had a lower saturated fat: polyunsaturated fat ratio.  Interestingly during the ‘chickpea phase the participants had significantly lowered total cholesterol and LDL cholesterol levels, low density lipoprotein cholesterol, thought to be the ‘bad guy’ cholesterol linked to heart disease, and also had better markers for blood sugar control (they showed lower fasting insulin levels and lower insulin resistance).  Analysis by the scientists revealed that it was the dietary fibre content of the chickpeas that was having the greatest effect on these health indicators.  The authors comment that their results warrant larger studies in groups who have problems with high cholesterol levels and/or poor blood sugar control (such as individuals with type II diabetes or insulin-resistance syndrome).

Another small study that was published in 2006(2) showed similar benefits of including chickpeas in the diet.  The study compared the effects of a chickpea-supplemented diet to those of a wheat-supplemented diet on cholesterol levels.  The 47 participants ate a chickpea-supplemented diet for at least 5 weeks and then a wheat-supplemented diet for at least 5 weeks.  The serum total cholesterol and LDL cholesterol levels were significantly lower after the chickpea-supplemented diet as compared with the wheat-supplemented diet.

A diet that is high in fibre has been linked to numerous health benefits in most areas of the body from the: heart, where it seems to have positive effects on blood pressure and risk of heart disease; digestive system where it seems to be useful to sufferers of irritable bowel syndrome (IBS), constipation and diverticulitis and the immune system where there seems to be a link with reduced risk of cancer.  A high fibre diet also appears to be very useful in blood sugar control and also appetite control as it gives us the feeling of fullness and helps to control satiety.  The recommended daily intake for fibre in the UK is currently set at 18g/d, however for optimal health many experts regard at least 25g per day as necessary.  In the UK our average intake is low at only 12g/d.

Chickpeas can be easily incorporated into salads, curries, dips (e.g. hummus), veggie-burgers, casseroles and stews....the list is endless.  If you are using canned chickpeas (which are very convenient and still nutritious) go for those in water with no added salt or sugar.

(1)Pittaway JK, Robertson IK, Ball MJ.  2008.  Chickpeas may influence Fatty Acid and fiber intake in an ad libitum diet, leading to small improvements in serum lipid profile and glycemic control.  J Am Diet Assoc. 108:1009-13.
(2) Pittaway JK, Ahuja KD, Cehun M, Chronopoulos A, Robertson IK, Nestel PJ, Ball MJ.  2006.  Dietary supplementation with chickpeas for at least 5 weeks results in small but significant reductions in serum total and low-density lipoprotein cholesterols in adult women and men.  Ann Nutr Metab.  50(6):512-8.

Written by Ani Kowal

On the 30th May  I wrote about the importance of Vitamin D for health and concentrated mainly on the link to cancer prevention.

Yesterday a study was published in the Archives of Internal Medicine(1) which adds to the growing body of research that links low vitamin D levels to poorer heart health.

This particular study involved a group of 18225 middle aged and older men (aged 40-75 years).  The men were free of diagnosed heart disease at the initial blood collection.  They were then followed for 10 years and in this time 454 developed heart attacks (which were either fatal or non fatal).  The study scientists then compared the blood levels of vitamin D in those men who had suffered a heart attack to a group of 900 similar men (matched for certain factors such as age and smoking status) who had not.  The results showed that men with low blood levels of vitamin D were at increased risk of heart attack compared to men with sufficient levels.  Even men with intermediate blood levels of vitamin D were at increased risk of heart attack.

The findings are significant as the scientists adjusted the results to exclude a whole host of other possible confounding factors such as family history of heart attack, weight (Body Mass Index), alcohol consumption, physical activity levels, history of diabetes, blood pressure, ethnicity, omega 3 fatty acid intake and cholesterol levels.  Even when these factors were taken into account the men with low vitamin D levels were twice as likely to experience a heart attack than those with high vitamin D levels.

The authors of the study conclude that “Low levels of 25(OHD) [vitamin D] are associated with a higher risk of myocardial infarction [heart attack] in a graded manner, even after controlling for factors known to be associated with coronary artery disease”

Previous studies have linked low vitamin D levels to atherosclerosis (hardening of the arteries), congestive heart failure and high blood pressure.  As I mentioned in my previous post on vitamin D many of us in the UK may not have adequate levels of vitamin D in our blood.  A supplement of 12mcg/d (around 500iu) could be useful to those who rarely get out in the sunlight or during the autumn and winter months.

It is not entirely understood why vitamin D is so important for the health of the heart.  There are indications that vitamin D acts to reduce the production of pro-inflammatory chemicals (cytokines) which are linked to heart disease and may even increase the production of anti-inflammatory chemicals which are protective.  Vitamin D may also have an effect on certain hormones which play an important role in the regulation of blood pressure. 

(1)Giovannucci E et al.  2008.  25-Hydroxyvitamin D and risk of myocardial infarction in men: a prospective study.  Arch Intern Med.  168:1181-1187

Written by Ani Kowal

Now that it is getting warmer (I was in London this weekend and it was a real scorcher!) it is essential that we consume adequate fluids throughout the day in order to keep properly hydrated.  Dehydration occurs, technically, when the loss of water from the body equates to 1% of the body’s weight.  It is important to drink before feeling thirsty as the sensation of thirst usually occurs after the body is already more than 1% dehydrated.

Keeping hydrated is important in order for us to function at our best.  Dehydration actually impairs short-term memory and can make us feel fatigued and irritable and is linked to the occurrence of headaches.  However, what we chose to quench our thirst can have a real impact on our health and waistlines!  I would highly recommend sticking to water as a thirst preventer and quencher.

A single can of regular soft drink may contain 40-50g of sugar.  If you were to drink one can a day in addition to your daily regular food intake you could gain 5kg of weight in one year!  The International Association for the Study of Obesity recognise that energy dense drinks represent a significant contributing factor in the rise in childhood obesity.  Soft drinks represent liquid calories and last year an analysis of 88 medical studies(1) concluded that there are clear associations between soft drink intake and increased energy intake and body weight. Soft drink intake was also associated with lower intakes of important nutrients (such as calcium and vitamins) and with an increased risk of several medical problems such as diabetes.

What about ‘diet’ soft drinks?  Artificial sweeteners are not something I can get excited about and I personally do not think they have any part to play in achieving a healthy balanced diet.  With respect to weight loss and/or weight maintenance there is evidence to suggest that artificial sweeteners may actually stimulate the appetite(2,3,4) and lead to increased calorie intake.  It is thought that the sweetness without the calories does not satiate the body and hence appetite is increased and subsequent calorie intake may be greater than if a regular drink had been consumed in the first place.

Pure fruit juices and fruit smoothies are often seen as the ‘healthy’ option.  Of course, these juices are more nutritious than a sugar-filled soft drinks but they do represent added calories if drunk in addition to normal daily intakes.  They are also high in natural fruit sugar (fructose) which has been linked to obesity and diabetes.  I would suggest limiting juice consumption to one glass per day with breakfast or as part of a meal but not for use as a regular thirst quencher or hydrator.

At the end of the day plain old water wins hands down in my opinion!

(1) Vartainian LR et al.  2007.  Effects of soft drink consumption on nutrition and health: a systematic review and meta-analysis.  Am J Public Health.  97:667-675
(2) Rogers PJ & Blundell JE.  1989.  Separating the actions of sweetness and calories: effects of saccharin and carbohydrates on hunger and food intake in human subjects.  Physiol Behav.  45:1093-1099
(3)Tordoff MG & Alleva AM.  1990.  Oral stimulation with aspartame increases hunger.  Physiol Behav.  47:555-559
(4) Lavin JH et al.  1997.  The effect of sucrose and aspartame sweetened sweetened drinks on energy intake, hunger and food choice of female moderately restrained eaters.  International Journal of Obesity.  21:37-42

Written by Ani Kowal

In Part I I mentioned that UV light can cause damage to the skin and contribute to photo-ageing through the initiation of inflammation.  The long chain omega 3 fatty acids EPA (Eicosapentaenoic acid) and DHA (docosahexaenoic acid) found in oily fish such as salmon, trout, sardines and mackerel as well as the shorter chain alpha-linolenic acid found abundantly in flax seeds acids are used by the body for the production of potent anti-inflammatory chemicals.  Including these omega 3 fatty acids in the diet may help to reduce sun induced inflammation, UVB skin sensitivity and may also help in the prevention of sunburn(1,2,3).

As mentioned in previous posts, omega 3 fatty acids are essential for optimal health for numerous reasons and many of us do not get adequate amounts from our daily diet.  If you are not a regular fish eater, or are vegetarian you may wish to consider taking a fish oil supplement to provide EPA (around 300mg per day) and DHA (around 200mg per day) or a vegetarian flaxseed oil (around 1000mg per day) supplement.  This could be useful to give the skin added natural sun protection and provide the body with a regular source of these essential fats.

Finally I would like to bring your attention to two studies(4,5).  They are of particular interest to me since they looked at cocoa consumption in relation to protection against sunburn.  Really dark chocolate (minimum 85% cocoa solids) is a passion of mine and I tend to indulge in a few squares at least a couple of times a week!  These studies have shown that consumption of flavanol (naturally occurring plant compounds) rich cocoa daily for 12 weeks reduced the risk of sunburn when skin was exposed to UV rays.  The major flavonols to be found in cocoa are called epicatechin and catechin, and it seems as though they are the components within cocoa that are important for boosting sun protection.  The ingestion of high flavanol cocoa led to increases in blood flow to the skin and layers below the skin, and to increases in skin thickness and hydration.

This is not a plug to justify regular chocolate binges (although it does help me to feel better about my dark chocolate habit)!  The cocoa used in these studies, and other studies that link cocoa to health benefits such as lowered risk of heart disease, was high flavanol cocoa and only a very small amount was used daily (around 350mg).  I am fond of drinking black cocoa but it is an acquired taste, as is the bitter high % cocoa chocolate that I so adore.  Sugary, sweet milk chocolate won’t provide the health benefits discussed (sorry to be the bearer of sad news!).  Flavonoids in general are found abundantly in fruits and vegetables, which, as mentioned in part I are important in sun protection through their provision of antioxidants.  Vegetables and fruit should form the core of a healthy diet and getting a good variety will give the body many of the nutrients that are needed for optimal health.

Obviously avoiding sun burn is exceptionally important, however, a slowly-acquired sun-tan may prevent against adverse effects of sun exposure in those who naturally tan easily.  Sun-sensitive individuals (those with fair skin and who burn easily) need to be careful as they have a higher risk for skin cancers.  Seeking shade, wearing a hat, adequate clothing and avoiding prolonged sunbathing is always advisable.  Sunscreens may also help but the ability of sunscreen to delay sunburn encourages many people to stay out in the sun for long periods of time and their skin (and health) may be negatively affected by this prolonged exposure. 

Please be sensible in the sun! 

(1) Rhodes LE et al.  1995.  Dietary fish oil reduces basal and ultraviolet B-generated PGE2 levels in skin and increases the threshold to provocation of polymorphic light eruption.  Journal of Investigative Dermatology.  105(4):532-535.
(2) Rhodes LE et al.  2003.  Effect of eicosapentaenoic acid, an omega-3 polyunsaturated fatty acid, on UVR-related cancer risk in humans. An assessment of early genotoxic markers.  Carcinogenesis.  24(5):919-925.
 (3) Takemura N et al.  2002.  Dietary, but not topical, alpha-linolenic acid suppresses UVB-induced skin injury in hairless mice when compared with linoleic acids.  Photochem Photobiol.  76(6):657-663.
(4) Heinrich U et al.  2006.  Long-term ingestion of high flavanol cocoa provides photoprotection against UV-induced erythema and improves skin condition in women.  Journal of Nutrition.  136(6):1565-1569.
(5) Neukam K et al.  2007.  Consumption of flavanol-rich cocoa acutely increases microcirculation in human skin.  Eur J Nutr.  46: 53-56

Written by Ani Kowal

Researchers at the Institute of Food Research in Norwich, have just published a study(1) indicating that probiotics (‘good’ bacteria) may help to keep hay fever symptoms at bay.

The researchers of this small study wanted to investigate whether the ‘good bacteria’ Lactobacillus casei Shirota (found in many probiotic supplements, yoghurts and drinks) played a role in modulating the symptoms of hay fever (seasonal allergic rhinitis).  Hay fever sufferers were given a milky drink, with or without the good bacteria, each day for five months.  The scientists kept track of, and compared the changes in, the immune system of the participants by collecting blood samples before, during and after grass pollen season.  

It was found that the probiotic being tested changed the way the body's immune cells responded to grass pollen.  The hay fever sufferers that had been drinking the probiotic containing drink had lower levels of the chemicals (interleukin 5 and 6 and interferon-gamma) partly responsible for the production of hay fever symptoms in the body.  They also had higher levels of specific antibodies (immunoglobulin G and E) which are associated with playing a protective role in allergy reactions.

The authors of the study conclude that “These data show that probiotic supplementation modulates immune responses in allergic rhinitis and may have the potential to alleviate the severity of symptoms.”

This was only a small study and the authors plan to do further work to further elucidate the role that probiotic ‘good’ bacteria may play in changing the immune status of hay fever sufferers.  As I mentioned in my post dated 19th May the good/friendly bacteria in our digestive system have been linked to positively enhancing the action of our immune system through their production of a variety of substances.  This study adds to the growing body of evidence which suggests that the bacteria in our digestive systems may be very important in affecting our overall health.

(1) Ivory K et al.  2008.  Oral delivery of Lactobacillus casei Shirota modifies allergen-induced immune responses in allergic rhinitis. Clin Exp Allergy. 2008 May 28. [Epub ahead of print]

Written by Ani Kowal

In my last post I wrote about the importance of vitamin D and sensible sunlight exposure.  This led me to start investigating natural ways to prevent skin damage from the sun (photo-damage) and sunburn.  The concept of photo-protection by dietary means is gaining increasing amounts of attention from the scientific community. 

Sun exposure leads to photo-ageing, with chronic sun exposure being a major contributor to ageing skin which is characterised by wrinkling, loss of elasticity, increased skin fragility and slower wound healing.  This photo-ageing probably occurs for a number of different reasons:

1. UV light can damage skin cell DNA via production of destructive ‘free-radical’ molecules .
2. UVB rays seem to induce the synthesis of enzymes which cause collagen, (and other skin tissue components), in the skin to degrade, this contributes to wrinkling, loss of elasticity and fragility.
3. UV light can also induce inflammation in the skin which contributes to photo-ageing.

Luckily there are some natural ways that can help us to protect our skin from sun damage. 

Antioxidants may help to ‘quench’ the destructive free radical molecules and therefore protect against photo-damage.  Specifically; beta-carotene, lycopene, lutein, vitamin C and vitamin E seem to be most helpful.  These plant constituents are involved in the light-protecting system in plants and may contribute to the prevention of UV damage in humans.  As nutrients they are ingested in the diet and are then distributed into the skin tissues where they provide the body with photo-protection.  

A diet rich in colourful fruits, vegetables, nuts and seeds will provide plentiful amounts of these antioxidants.  Beta carotene, lutein and lycopene are all carotenoids.  Carotenoids are a family of over 700 naturally occurring yellow, red and orange pigments found in vegetables and fruits.  Good sources include carrots, sweet potatoes, tomatoes, squash, peppers, cantaloupe melons, nectarines, papaya, mango and dark green vegetables such as spinach, watercress and asparagus.  Introducing a good mix of these fruits and vegetables in the diet will help keep carotenoid levels in the body high.

Absorption of these carotenoids from foods into the body is greatly affected by fat.  Without a fat source almost no carotenoids will be absorbed.  Fat acts as a carrier for the nutrients.  Now, I am not suggesting that you drown your vegetables or salads in ‘any old lard’, however I am a firm believer in using small amounts of olive oil in dressings and cooking.  Or including some nuts, seeds or olives in salads will also be helpful in order to gain maximum absorption of these important nutrients.

Two human studies have looked at tomato consumption and blood serum lycopene levels with regards the risk of sunburn(1,2).  The study groups were given lycopene or tomato-derived products rich in lycopene (mixed with olive oil) for 10-12 weeks.  Their blood serum lycopene levels increased with supplementation and they experienced a decrease in their sensitivity toward sunburn.  Sunburn damage was up to 48% lower in the groups receiving lycopene/tomato paste compared to the control groups.

Supplements containing antioxidants such as the carotenoids, vitamin C and vitamin E may also be useful in slowing down the time of development and grade of UVB induced sun damage(3).  If you feel that you are not getting a good supply of a variety of different fruit and vegetables daily in your diet, you may wish to consider taking a supplement to boost your levels of sun-protective antioxidants, especially in the sunny months or prior to a sunny holiday. 

Check back soon for Part II where I will be looking at how nutrition can help protect the skin from the inflammatory damage that the sun can cause.

(1) Stahl W et al.  2001.  Dietary tomato paste protects against ultraviolet light–induced erythema in humans.  Journal of Nutrition.  131(5):1449-1451.
(2) Aust O et al.  2005. Supplementation with tomato-based products increases lycopene, phytofluene, and phytoene levels in human serum and protects against UV-light-induced erythema.  Int J Vitam Nutr Res.  75(1):54-60. 
(3) Greul AK et al.  2002.  Photoprotection of UV-irradiated human skin: an antioxidative combination of vitamins E and C, carotenoids, selenium and proanthocyanidins.  Skin Pharmacol Appl Skin Physiol.  15(5):307-315

Written by Ani Kowal

Vitamin D appears to be receiving a lot of attention in the scientific and medical press at present with well over 20 studies due for publication in June alone and many, many more already published in 2008.  In fact, as I started to research for this post the current issue of The Proceedings of The Nutrition Society arrived through my letterbox (Volume 67 No.2) and two of the featured papers covered the importance of vitamin D (one in relation to cancer and one in relation to the treatment and prevention of osteoporosis).

Vitamin D is called the sunshine vitamin, though technically vitamin D is a hormone, as it is produced in the body when the skin is exposed to the UVB rays in sunlight.  In theory spending just 10-15 minutes in the sun everyday should supply all the vitamin D that we need.  However, many of us do not get enough sun on our skin to generate adequate amounts of vitamin D especially in the autumn and winter months.  A recent analysis(1) found that there is a global widespread insufficiency of this vital nutrient and there is evidence from the National Diet and Nutrition Surveys (NDNS) which suggests that in the UK vitamin D deficiency is a real problem (2,3,4,5).  The problem is made worse in the older generations since, as we age our bodies find it increasingly difficult to manufacture vitamin D.

This does not make for good news since vitamin D is vital for our health.  Not just the health of our bones and teeth but a for our hearts (the vitamin may protect against atherosclerosis, heart attack and high blood pressure), our digestive systems, the immune system (there is increasing evidence to show that vitamin D is important in the prevention of cancer), blood sugar control (and the prevention of type I and type II diabetes and insulin resistance), muscles, brain (deficiency is linked to depression and mood), fertility and skin health.  Quite a list!

I would like to write a bit more about the link between vitamin D and cancer.  We are constantly told by the media to avoid the sun as it increases our risk of a certain type of skin cancer called ‘malignant melanoma’.  However evidence is now mounting to suggest that insufficient sunlight exposure and low vitamin D levels actually increase the risk of several types of internal cancers such as breast, prostate, colon, bladder, kidney, lung, pancreas and ovary (to name but a few) (6,7).  Just as I was finishing this post a study was published (8) which looked at UVB exposure, vitamin D levels and breast cancer risk across 107 countries.  The authors of the study found that higher blood vitamin D levels were associated with lower rates of breast cancer and UVB exposure had a protective effect on the risk of breast cancer (these effects were independent of potential confounding factors such as fertility rate, overweight, alcohol intake, animal energy intake).  Vitamin D seems to have many cancer protective properties;  it can prevent cells from multiplying and can also specifically induce the death of cancer cells. 

It certainly seems that the sun is very important for our optimal health and wellbeing!

It is essential to be safe in the sun and avoid getting burned and baked, malignant melanoma is a particularly nasty skin cancer.  However , the risk of this type of skin cancer is relatively low in comparison to other forms of cancers and staying out of the sun completely will probably do more harm than good with regard to health and overall cancer risk.  For more interesting information about the benefits of sunlight for health please visit the Sunlight Nutrition And Health Research Centre, the information there is well presented and backed up by significant amounts of good evidence.

The UV in sunlight is believed to be our main source of vitamin D with only small amounts being found in food sources such as oily fish (mackerel, salmon and sardines)and eggs.  Recently, however, there has been mass debate about whether UV exposure in the UK is sufficient to keep vitamin D levels optimal for health.  I mentioned earlier that most of us in the UK are falling short of recommended levels.  If you rarely get out into the sun you may wish to consider a vitamin D supplement which provides around 12mcg/day (around 500iu).  Such a supplement may be particularly useful during the autumn and winter months.

(1) Hagenau T et al.  2008.  Global vitamin D levels in relation to age, gender, skin pigmentation and latitude: an ecologic meta-regression analysis.  Osteoporosis International May [E publication ahead of print]
(2) Finch S et at.  1998.  National Diet and Nutrition Survey of People aged 65 Years and Over.  London: H. M. Sationery Office.
(3) Gregory L et al.  2000.  National Diet and Nutrition Survey of People aged 4-18 years. Vol 1.  Report of the Diet and Nutrition Survey.  London:  The Stationery Office
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Written by Ani Kowal