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
(4) Henderson L et al.  2002.  National Diet and Nutrition Survey: Adults Aged 19-64 years.  Vol 1: Types and Quantities of Foods Consumed.  London: The Stationery Office
(5) Hypponen E & Power C.  2007.  Hypovitaminosis D in British adults age 45y: nationwide cohort study of dietary and lifestyle predictors.  Am J Clin Nutr.  85:860-888.
(6) Grant WB.  2002.  An estimate of premature cancer mortality in the U.S. due to inadequate doses of solar ultraviolet-B radiation.  Cancer.  94:1867-1875
(7) Grant WB & Garland CF.  2006.  The association of solar ultraviolet B (UVB) with reducing risk of cancer: multifactorial ecologic analysis of geographic variation in age-adjusted cancer mortality rates.  Anticancer Research.  26:2687-2699
(8) Mohr SB et al.  2008.  Relationship between low ultraviolet B irradiance and higher breast cancer risk in 107 countries.  Breast J.  14:255-60

Written by Ani Kowal

The symptoms of hay fever may well be irritating and even distressing at times.  As I said in Part I I do not suffer from the condition so this may well sound easy for me to say, but trying not to get too upset and stressed about your hay fever could be a great help.  This is important to mention because stress(1) has been linked to the production of inflammatory agents in the body and could hence further aggravate your symptoms thus starting up a vicious cycle.

As discussed previously hay fever is an inflammatory condition.  A natural agent that would be highly useful in mediating the inflammatory reactions in the body is the long chain omega 3 fatty acid, Eicosapentaenoic Acid or EPA.  As well as having a general anti-inflammatory role EPA may actually help to prevent hay fever.  A study in 2003(2) demonstrated that individuals with a high intake of dietary EPA had a 55% reduction in their incidence of hay fever compared with persons who consume low amounts of dietary EPA.

EPA is naturally found in oily fish such as mackerel, salmon, trout and sardines.  As well as aiding the production of potent anti-inflammatory chemicals in the body it is also beneficial to the health of the heart, brain, eyes, nerves, bones, digestive system and skin (and I am sure I will be mentioning omega 3 fatty acids in future blog postings!).  Many of us do not eat these types of fish regularly (two portions per week is usually recommended) and hence a daily fish oil supplement (providing around 300mg of EPA and 200mg DHA) may be very useful for the prevention of hay fever and even to promote optimal health and wellbeing.  For vegetarians and vegans flaxseed oil (1000mg daily) can provide omega 3 fatty acids in the form of alpha linolenic acid which the body then bio-converts to EPA (the long chain form). 

One other natural remedy which can be helpful in the treatment of hay fever is the herb Butterbur (Petasites hybridus). This herb seems to exhibit anti-inflammatory activity and anti-allergic properties.   The British Medical Journal published a study(3) which compared Butterbur supplementation with the conventional antihistamine drug cetirizine (prescribed in the UK under the name Zirtek).  Both treatments were equally effective in reducing hay fever symptoms.  However, the drug cetirizine tended to cause side effects such as fatigue and drowsiness.  The authors of the study concluded that:  “The effects of butterbur are similar to those of cetirizine in patients with seasonal allergic rhinitis.....Butterbur should be considered for treating seasonal allergic rhinitis when the sedative effects of antihistamines need to be avoided”.

As an interesting point antibiotics used in children in their first 2 years of life have been associated with a 2-3 fold increased risk of hay fever(4).  As well as destroying the bacteria that cause illness in the body antibiotics also kill the healthy bacteria that live in the digestive system.  As mentioned in a previous posting these friendly bacteria have been shown to positively affect the immune system, which is responsible for allergic and inflammatory responses in the body, so a prebiotic and probiotic supplement may be useful to anyone who has been recently exposed to antibiotics or as an immune boosting aid (see post dated 19/05/08 for more detail about pre- and probiotics for immune health).

And finally, a study last year (5) found that almost 50% of hay fever suffers seem to be highly sensitive not only to typical allergy triggers like grass, tree pollens, dust and animal hair but also to things like cold air, perfumes, cigarette smoke and household cleaning products.  So, if you find that you often suffer from symptoms like itchy eyes and stuffy or runny nose you may find it useful to take a product containing vitamin C and bioflavonoids (as discussed in Part I) all year around as a preventative, anti-allergic measure.

(1) Maes M et al.  2000.  In humans, serum polyunsaturated fatty acid levels predict the response of proinflammatory cytokines to psychologic stress.  Biol Psychiatry.  47(10):910-920.
(2) Nagel G et al.  2003.  The influence of the dietary intake of fatty acids and antioxidants on hay fever in adults.  Allergy.  58(12):1277-1284.
(3) Schapowal A.  2002.  Randomised controlled trial of butterbur and cetirizine for treating seasonal allergic rhinitis.  BMJ.  324:144-146
(4) Wickens K et al.  1999.  Antibiotic use in early childhood and the development of asthma, hay fever and eczema. Clin Exp Allergy.  29:766-771
(5)Shusterman D and Murphy MA.  2007.  Nasal hyperreactivity in allergic and non-allergic rhinitis: a potential risk factor for non-specific building-related illness.Indoor Air.  17:328-333

Written by Ani Kowal

Last weekend (18/05/08) The Sunday Times ran a story entitled “Superfood celery combats brain diseases”.  Quite timely I thought, as I was in the middle of preparing a post on the important role that dietary flavonoids , also known as bioflavonoids  (a group of over 4000 types of polyphenol plant compounds), play in maintaining mental health e.g. memory, learning and general mental performance.  The newspaper article focussed on the flavonoids, luteolin and diosmin, found in celery and how they may be important in slowing the progress of brain diseases such as Alzheimer’s disease.

A recently published medical review paper(1) brought together evidence for the role of dietary derived flavonoids and mental health.  In this paper Dr Jeremy Spencer, a researcher and lecturer at my old University, highlights a number of studies in both humans and animals which have found that flavonoids, from a variety of dietary sources such as grapes, tea, blueberries, cocoa, onions, broccoli and tomatoes (to name but a few), have beneficial effects on cognitive (mental) performance.  He postulates that the benefits come from the ability of the flavonoids to protect brain neurones, reduce neuronal inflammation, enhance neuronal function and even stimulate neuronal regeneration (regrowth). 

The paper is extensive, however I would just like to mention one study that is reviewed(2).  In this study 1640 individuals, all over the age of 65, were followed for ten years and their dietary habits assessed over that time.  All of them were free of dementia at the start of the study.  Cognitive (mental) performance was examined four times over the ten year period.  Flavonoid intake was associated with a significantly better cognitive performance at the start of the study and throughout the study period.  The individuals with the highest flavonoid intakes were found to have better preservation of mental performance with ageing than subjects with the lowest intakes of flavonoids.  After 10 years the individuals with the lowest intakes were found to have lost an average of 2.1 points on a test of mental performance (the Mini-Mental State Examination) compared to those with the highest intakes who had lost on average only 1.2 points.  Such data provides a strong indication that regular dietary flavonoid consumption may have a positive effect on preserving mental performance with ageing.

As Dr Susanne Sorensen of the Alzheimers Society is quoted as saying in the newspaper “we know a healthy balanced diet can reduce dementia risk.  This work reinforces the need to eat a diet rich in fruits and vegetables”.  There are many dietary factors which can contribute to a healthy brain and positive mood and I am sure that I will address these factors in my future writings!

It is clear that a diet rich in a variety of different vegetables and fruits is really very important for all aspects of health.  There is NO substitute for a diet plentiful in a variety of vegetables and fruits.  Choosing produce with a mixture of colours will provide an array of different flavonoids.  Flavonoid supplements do exist and these may be helpful to take in addition to a healthy diet as a means of boosting intakes.  If you do choose to take a supplement look out for one that provides an assortment of many different flavonoids (they may be labelled as bioflavonoids).

(1) Spencer JPE.  2008.  Food for thought: the role of dietary flavonoids in enhancing human memory, learning and neuro-cognitive performance.  Proceedings of the Nutrition Society.  67:238-252
(2) Letenneur L et al.  2007.  Flavonoid intake and cognitive decline over a 10 year period.  Am J Epidemiol.  165:1364-1371

Written by Ani Kowal

No excuse is needed for me to get outside and enjoy the warm weather!  I relish spending as much time as possible walking in the countryside amongst the grasses and flowers.  However, it is estimated that up to 25% of the UK population suffer from hay fever, and for affected individuals spring and summer signify the seasons of sneezing, sniffles and stress.

Symptoms of hay fever, which is also known as seasonal allergic rhinitis, can include sneezing, watering and itchy eyes, a runny nose, headaches and skin rashes.  This can seriously affect outdoor enjoyment at a time when everyone else seems to be bathing themselves in the blissful warmth.

These irritating and upsetting symptoms occur when membranes lining the nose and eyes become aggravated and inflamed by airborne pollen.  The pollen triggers a type of immune cell, called a mast cell, to release the chemical histamine in those membranes.  The histamine then stimulates an inflammatory reaction in the body which produces the characteristic symptoms.

Conventional treatment for hay fever is based on antihistamine pills, anti-inflammatory medication such as steroid nasal sprays, and decongestants such as ephedrine. However, an increasing number of people are not content with taking such medications on a long term bases.  Fortunately, there are a number of natural strategies that can offer very real relief from the symptoms of hay fever.

Vitamin C and the bioflavonoid (plant compound) quercetin (naturally rich sources include apples, onions and green tea) both seem to act as natural anti-histamines in the body and supplementation may be useful in helping to control hay fever symptoms(1-6).  500mg of vitamin C taken 3 times a day throughout the hay fever season should prove helpful together with around 300-400mg of quercetin 2-3 times daily.  It is a good idea to take the two supplements together as bioflavonoids appear to protect and enhance the action and absorption of vitamin C (naturally vitamin C is found as a complex molecule bound up with various flavonoids).

Bromelain, an enzyme found naturally in pineapples, also seems to be useful in dampening down the bodily immune response associated with hay fever symptoms(7-9).  Supplements which contains both Quercetin and Bromelain in a capsule form are available and may be useful to try in addition to a vitamin C.

Nettle (Urtica dioica) is a natural herbal remedy which has been traditionally used to treat allergic conditions such as hay fever.  It seems to exhibit anti-allergy properties.  In a double-blind scientific study(10), freeze-dried extract of stinging nettle leaf led to a slight reduction in symptoms of hay fever, including sneezing and itchy eyes. In practice individuals seem to find that nettle in combination with vitamin C and bioflavonoids works well at controlling the worst of their hay fever symptoms and supplements combining all of the aforementioned agents in one product are available.  Taking such a supplement throughout the spring and summer months may well bring some welcome relief.

Remember to check back soon for more advice in Part II

References
(1)Balabolkin II et al.  1992.  Use of vitamins in allergic illnesses in children.  Vopr Med Khim.  38:36-40.
(2)Bucca C et al.  1990.  Effect of vitamin C on histamine bronchial responsiveness of patients with allergic rhinitis.  Ann Allergy.  65:311-314.
(3)Cathcart RE.  1981.  Vitamin C, titrating to bowel tolerance, anascorbemia, and acute induced scurvy.  Medical Hypotheses.  7:1359-1376
(4)Holmes HM et al.  1942.  Hay fever and vitamin C. Science.  96:497
(5)Ruskin SL.  1945.  High dose vitamin C in allergy. Am J Dig Dis.  12:281
(6)Thornhill SM et al.  2000.  Natural treatment of perennial allergic rhinitis.  Alternative Medicine Review.  5(5):448-454.
(7)Gaspani L  et al.  2002.  In vivo and in vitro effects of bromelain on PGE(2) and SP concentrations in the inflammatory exudate in rats.  Pharmacology.  65(2):83-86.
(8)Hale, L. P. et al.  2002.  Bromelain treatment alters leukocyte expression of cell surface molecules involved in cellular adhesion and activation.  Clin Immunol.  104(2):183-190.
(9)Ito C et al.  1979.  Anti-inflammatory actions of proteases, bromelain, trypsin and their mixed preparations.  Folia Pharmacol Japan.  75:227-237.
(10)Mittman P.  1990.  Randomised double-blind study of freeze-dried Urtica dioica in the treatment of allergic rhinitis.  Planta Med. 56:44-47

Written by Ani Kowal

Whilst writing my last post about zinc and the common cold I came across some interesting research and evidence about probiotics and how they may be useful in enhancing the function of our immune system.  Probiotics are supplements containing ‘beneficial’ or friendly bacteria which inhabit the intestines.  These friendly bacteria produce various substances in our bodies, such as acetic acid, lactic acid and hydrogen peroxide, which  may help to counteract detrimental bacterial and viral infections in all parts of the body (not just in our digestive systems). 

Two studies (1,2) have looked specifically at how taking probiotics daily can prevent us from catching colds and how they may affect the duration and severity of cold symptoms if we do succumb.  Results suggest that taking probiotic supplements for at least three months had a positive effect on the cells of the immune system, shortened common cold episodes by almost 2 days and reduced the severity of symptoms!

Evidence for the various health benefits of taking daily probiotic and/or prebiotic supplements is growing each year.  Probiotics work by supplying 'beneficial/friendly' bacteria to the digestive system and Prebiotics, often called FOS or fructooligosaccharides, work by promoting the continued growth of friendly bacteria present in the intestines.  FOS act as a food source that only the beneficial bacteria can use to grow.  Personally I have taken prebiotics for many years now.  One of my professors at university, Prof Glen Gibson, has published several scientific papers and studies concerning the benefits of prebiotics and probiotics to health and he spurred me into taking a daily supplement. 

Many products are available that combine Probiotics and Prebiotics together.  After a month of taking the combined supplement you may wish to switch and use a prebiotic/FOS supplement only.  This will help to maintain high levels of the beneficial bacteria in the digestive system.
 
References
(1) de Vrese M et al.  2005.  Effect of Lactobacillus gasseri PA 16/8, Bifidobacterium longum SP 07/3, B. bifidum MF 20/5 on common cold episodes:  a double blind, randomized, controlled trial.  Clinical Nutrition.  24(4):481-491
(2) Tubelius, P et al.  2005.  Increasing work-place healthiness with the probiotic Lactobacillus reuteri:  a randomised, double-blind placebo-controlled study.  Environ Health.  4(1):25

Written by Ani Kowal

Recently my mum came back from a trip with a heavy springtime cold, a member of her travelling party had kindly passed on the infection and poor mum was suffering with the typical symptoms of a tickly throat, headache and runny nose.  Colds are caused by viruses and our susceptibility to these infections is largely dictated by the efficiency of our immune system.  A healthy diet providing our bodies with optimal nutrition may help to keep our immune systems strong and protect us from infection.

The symptoms of a common cold tend to last from a few days to a couple of weeks but most cases are over within one week (fortunately my mum is fit and healthy and her cold only lasted a few days!).   There is mixed evidence with regards prevention and treatment of colds with complementary health methods but I am always one to try ‘beating the bug’ naturally!

One of the nutrients that is essential for the efficient functioning of our immune system is zinc and last month a study published in the Journal of Infectious Diseases (1) found that using lozenges containing zinc at the first sign of a cold (within 24 hours of developing symptoms) was associated with reduced duration and severity of cold symptoms.  This study adds weight to previous research indicating that zinc lozenges, sucked in the mouth and not swallowed whole, seem to help prevent infection from the common cold and also accelerate recovery once infected. 

This most recent study involved 50 volunteers who had suffered cold symptoms, such as a cough, runny nose and muscle aches, for less than 24 hours. Half of the participants were given zinc lozenges, containing about 13mg of zinc, and half were given inactive ‘placebo’ lozenges (the two groups were not aware of which lozenges they had been assigned).  They then took one lozenge every 2 to 3 hours while awake.  The group taking the zinc lozenges had cold symptoms for an average of 3 days less than those taking the placebo.  Every cell in our body needs zinc and the investigators believe that beneficial clinical effects seen in the zinc group were due to the antioxidant and anti-inflammatory effects that this nutrient has in the body.

Lozenges and dissolvable tablets and drinks often contain vitamin C, another nutrient which some studies suggest (2) may be useful in reducing the severity and duration of cold symptoms.  If you feel a cold coming on it may be useful to try sucking on a lozenge every three hours or so while symptoms persist.  

References:
(1) Prasad AS, Beck FW, Bao B, Snell D, Fitzgerald JT.  2008.  Duration and severity of symptoms and levels of plasma interleukin-1 receptor antagonist, soluble tumor necrosis factor receptor, and adhesion molecules in patients with common cold treated with zinc acetate.  J Infect Dis.  Mar 15;197(6):795-802
(2) Van Straten et al.  2002.  Preventing the common cold with a vitamin C supplement: a double-blind, placebo-controlled survey.   Adv Ther.  19(3):151-159

Written by Ani Kowal