Supplements

Jump to links for the following Fact Sheets: General Information Supplements How vitamines work Expert Advice on Specific Supplements and Vitamins Glucosamine Chondroitin Sulphate Vitamin D

Supplements    

• Introduction
• Vitamins
• Minerals
• Weight-loss supplements
• Why vitamins and micronutrients are sometimes important in weight loss

Introduction

In this section you will learn about the commonly known micronutrients. There is a lot of advertising by supplement manufacturers to try to convince you that taking supplements is vital to your health or will make you slim.

If you eat a balanced diet with lots of vegetables and fruit, you should not become deficient in any vitamins or minerals. However, as discussed in this section, vitamin and mineral supplements may sometimes be required when you are actively trying to lose weight and eating fewer kilojoules than your body needs, i.e. during your initial weight loss period.

Many foods have added vitamins and minerals (i.e. are fortified), so becoming deficient is usually quite difficult. There are several categories of people that could become vitamin or mineral deficient, including alcoholics, drug addicts, elderly people, sick people and long-term malnourished people such as those with anorexia nervosa. Overweight people, unless the diet is completely devoid of fruit and vegetables, should never risk becoming deficient in any micronutrients.

1.Vitamins

Vitamins are one of the essential micronutrients that your body needs to maintain its functions. Vitamin deficiencies were once very common and disorders such as beri-beri and scurvy were caused by people not having access to fresh fruits and vegetables. Today, vitamin deficiencies have become a rare occurrence in western societies and are usually only seen in select groups and sometimes newborn babies.

Vitamin and mineral deficiencies are caused by eating too little food as well as the wrong foods. Even if you reduce your kilojoule intake, you should still obtain more than enough vitamins in your diet. This is because many foods today are fortified with micronutrients. However there may be times when you need to take a vitamin or mineral supplement There are two groups of vitamins—the fat-soluble and the water-soluble—and these names relate primarily to the way that the body absorbs, processes and stores these vitamins. More information on water- and fat-soluble vitamins can be found in Bernard’s book, Healthy Intentions: Make it a Habit.

2. Minerals

Minerals are a range of chemical elements that have different functions in your body. Many of these functions still need to be fully investigated, but it seems very unlikely that they would help or hinder your weight loss. The nutritional minerals are the chemical elements that are found in the ash after the body or food is burnt. It is possible to become deficient in some of these elements in vegetarian-type diets or a poor diet in general and supplements may be needed in these cases.

3.Weight-loss supplements

The search for effective weight-loss drugs continues, but to date there are no overwhelmingly effective treatments for weight loss. Pharmaceutical drugs that you buy on prescription from your doctor go through rigorous scientific research and testing before being released and most of the claims that the pharmaceutical companies make, although sometimes exaggerated, can usually be substantiated.

This is not the case for the supplements and weight-loss pills that you buy over the counter from your pharmacy or local health food store. Usually they do not have to go through any sort of scientific tests to be marketed, and the manufacturers do not have to substantiate their claims.

Despite this lack of evidence, and even in the presence of evidence for little or no effectiveness, people keep buying weight-loss pills in the hope that they may help. It is easier to hope for the quick fix than it is to put in the hard work it takes to lose weight. Weight loss is difficult; it requires effort and determination and there is a high level of failure. So manufactures of these weight-loss supplements capitalise on desperate people who want an easy way out. But at this stage there is no easy way out.

There are no supplements that have any dramatic effect on weight loss. The only supplements that have been shown to have any effect in scientific research are capsaicin (a bitter component found in capsicums), caffeine (i.e. in coffee) and fibre. However,  the effects of many of these supplements is mild.

4. Why vitamins and micronutrients are sometimes important in weight loss

Although vitamins and various supplements do not cause you to lose weight, there are still reasons why you should still consider taking them. When starting your weight-loss program, you need by necessity a smaller food intake than your body requires. As you reduce the amount of food that you eat it will mean that you also reduce your daily supply of vitamins and minerals.

Vitamins and minerals are vital for your health and wellbeing and they do not contain any kilojoules so they do not contribute to weight gain. While you are trying to lose weight it is important to maintain an adequate vitamin and mineral intake. There are other proven benefits of vitamins, such as folate in pregnancy and glucosamine for helping joints.

In this section of the website I will systematically go through the vitamins, minerals and supplements that are available. I will attempt to provide a balanced view without bias so that you can make up you own mind regarding the available evidence. If I feel that a vitamin, mineral or supplement has a specific proven price I will provide it on this web site. I have personally reviewed the evidence for all of the supplements that are available for sale on this website. You can be sure that you both value for money and a scientifically proven product.

How vitamins work

• Introduction
• What they're not
• What they are
• Thirteen is lucky for some
• Made to measure
• Meet the family

Introduction

Vitamins are vital for our health and wellbeing, which is beyond doubt, having been proved on many occasions. A look at vitamins in the history of the world -and unfortunately still today in developing third world countries-has led and is leading to many people suffering from preventable killer diseases and other general complaints of ill health. So don't groan when your mum checks if you're taking your vitamins!

What they're not

So they're good for us, but they don't actually give us energy. That's the job of stuff like carbohydrates, fats and proteins. These are known as macronutrients, with vitamins and minerals being micronutrients.

Vitamins should be thought of being more like a hard working growth and maintenance crew, involved in watching over the everyday upkeep (and development, when young) of our bodies. Helping to keep things running smoothly and efficiently, preventing some things from going wrong, and putting other things right.

What they are

So what are they then? Vitamins are molecular compounds made of organic chemicals that cannot be produced by the human body, but are necessary for its survival. Organic means they contain carbon, and in addition to which they are made up from hydrogen, oxygen, and a few with nitrogen and/or other elements in lesser quantities. They can vary quite a bit in chemical structure and this can affect how they work, but all the possibilities are known and quite well understood by nutritionists today thanks to decades of research by American, British, and European scientists.

Thirteen is lucky for some

They are thirteen in number and come in two broad types: fat-soluble and water-soluble. This means that when solid they either dissolve in a solution of water or in fats and oils. The word solution comes from the Latin ‘solutio' which means, ‘a loosening', and this is crucial to the process of absorption into our bodies. So that the vitamin molecules can get to where they are either stored for future use, or used right away.

The fat-soluble are vitamins A, D, E and K. The water-soluble are the vitamin B group and vitamin C.

The water-soluble vitamins are like fast livers, they come and go. Being easily lost to us in perspiration (sweat) or urine (you know what that is). So consequently our bodies have a difficult job in holding onto them, and demand a constant repeat of supply.

The fat-soluble vitamins are less easy to get rid of, which can be a good thing, and a bad thing. It's good because the human body can build up stocks in case of a lack of supply; but if that supply line keeps on coming in too fast daily, then the advantage turns to disadvantage. The body's metabolism can't get rid of the excess amount, and in extremes, this can result in toxins being produced (known as hypervitaminosis).

So skipping your vitamins A, D, E and K now and then won't be a problem. But the body soon craves for the vitamin B's (there are eight of them) and vitamin C. They'll be quickly missed so make sure you don't develop a rapid deficiency. Especially so if you have a high intake of caffeine and alcohol (which are known as diuretics) as these could lead to increased vitamin loss.

Made to measure

Luckily though, not much is required in quantity. Vitamins are so effective that only tiny amounts need to be taken in each day through food or supplements. This is because they can be re-used several times before exhausting their goodness.

Due to this fact, only minute measurements are used for our US RDA's (United States Recommended Daily Amounts) like milligrams and micrograms. One milligram (1mg) is only one thousandth of one gram (1g), and one microgram (1mcg) is one millionth of one gram (1g). Sometimes other abbreviations like DV (Daily Values) or RDA may be used, this stands for Recommended Dietary Allowance, and these are slightly different from US RDA, which are based on them, as they use broader values.

Sometimes you may find IU on the packaging of purchased vitamin supplements. This means International Unit, and is an internationally recognised standard for biological activity of vitamins A, D, and E. One IU is a different amount, depending on which vitamin is expressed.

If your vitamins are of foreign origin, a strange symbol looking like a stylised letter ‘u' with an extra stroke dropping down from the lower left. This represents microns (one micron is one millionth of a meter) in the metric system, and although being a unit measure length rather than weight, can often be found on imported dietary supplement labelling and packaging, particularly from Europe.

Meet the family

So we know vitamins are vital, now let's meet them individually, find out some of the places where they can be found, and what they do.

• Vitamin A (an anti-cancer vitamin also known as Retinol)
  Vitamin A is very important for healthy eyes, especially for the formation of visual purple, which increases night vision. It also helps to keep our eyes from drying out and is good for nourishing the white of the eyeball. As well as eyes, vitamin A also aids the healthy upkeep and growth of our bones, hair, skin, teeth, mucous membranes and benefit's the immune system. The chief source of vitamin A is carotene or beta-carotene, which can be found in egg yolks, butter, cheese and yellow or orange fruits and vegetables. So carrots really do make you see in the dark!
• Vitamin B1 (Thiamine)
  This vitamin helps growth, digestion and the health of nerves and muscles. With the latter using up roughly a half of all the body's thiamine take up. A severe deficiency of this leads to the deadly disease known as beriberi, which causes paralysis and then death. Vitamin B1 is found in pulses, whole-wheat and other breads, pork, liver, milk, oysters and potatoes.
• Vitamin B2 (Riboflavin)
  Vitamin B2 is very important to the body's metabolism, in freeing energy from carbohydrates, fats and proteins in our food. It is very common in milk, pulses, eggs, cheese, nuts, yeast, mushrooms, dark green leaves, liver and kidneys. Its lack of presence can cause dandruff, cracked lips, other skin disorders and an inflamed tongue.
• Vitamin B4 (Folic Acid)
  Extremely important for the development of fetuses and for healthy blood by increasing the production of red blood cells (which carry oxygen around the body). It also aids in replacing cells and the use of amino acids for genes. A lack of this vitamin will result in certain forms of anaemia. It is to be found in many green vegetables, liver, kidneys, pulses, yeast, and mushrooms.
• Vitamin B6 (Pyridoxine)
  This vitamin helps in the absorption of proteins and the health of red blood cells. Its sources are red meat, poultry, fish, potatoes and bananas. If not present in sufficient quantities, it too can lead to anaemia.
• Vitamin B7 (Niacin or Nicotinic Acid)
  Needed for the freeing of energy from carbohydrates and fats, and for better cellular properties. To be found mostly in red meats, fish and poultry, as well as bread and milk. Without it pellagra and other skin conditions and diseases will occur.
• Vitamin B12 (Cyanocobalimin or Cobalimine)
  B12 is good for cell reproduction, especially in bone marrow where red blood cells come from, and healthy nerve tissue. The best sources for vitamin B12 are meat, fish, eggs and milk. A lack of B12 will result in anaemia or nervous disorders.
• Biotin (previously known as vitamin H)
  This works for our growth and delivery of energy through fatty acids, and probably aids healthy skin. Chief sources are milk, butter, egg yolks and yeast and liver, also, green beans. Consuming too many raw (uncooked) eggs will work against this vitamin. Deficiency problems are unknown though may include depression, nausea, and a lack of appetite.
• Pantothenic Acid
  This vitamin is needed for the body's metabolism and the production of hormones. It is very common in all foodstuffs and therefore deficiency conditions are unknown, but could be fatigue, stomach pains and skin complaints.

The vitamin B group numbers are apparently haphazard in fashion here because there used to be more which later proved to be vitamin like substances, and not actually vitamins. The difference being, these others whilst having similar properties and tasks could be produced by humans within our own bodies unaided, and proper vitamins cannot be.

• Vitamin C (an anti-cancer vitamin also known as Ascorbic acid)
  This vitamin is famous for curing scurvy. While most animals can make it internally, humans cannot. It's most important duties are the healthy upkeep of arteries, bones and teeth, the immune system (helping to fight against colds and the flu), the production of collagen for healthy skin and the healing of wounds and burns. It is to be found in all fruit and vegetables, specially the citrus fruits, tomatoes and potatoes. Severe lack of vitamin C will result in scurvy, teeth loss, bleeding gums and muscle wastage.
• Vitamin D (Calciferol)
  Vitamin D is indispensable for bone formation, helping to control their mineral composition, and keeping them strong and healthy. It is to be found in milk, eggs, margarine, butter, fish and fish oils; and also can be formed in our skin when we expose it to sunshine. Deficiency causes rickets in children and weakened bones in adults.
• Vitamin E (Tocopherol)
  Another anti-cancer vitamin. This keeps our cells healthy and was thought to affect fertility. It helps vitamin A to work better and might have anti-aging properties. It is present in green leaves, beans, wheat bread, margarine and vegetable oils, nuts and seeds. When lacking, unhealthy blood is the result.
• Vitamin K
  Vital for stemming blood flow from cuts and wounds (coagulating), it can be found in all green vegetables and as vitamin K2 can be formed by bacteria in our intestines. Deficiency will result in heamorrhaging of wounds (an inability to stop bleeding).

So there they are, helping us along our way, but we also need to help them by not over cooking our meals which leads to reduced vitamin content in the food we eat. Don't undercook mind, as that will lead to the much more immediate and serious problem of food poisoning!

Vitamins are also more common in fresh vegetables than frozen and steamed foods as opposed to boiled. Pesticide free and unprocessed foodstuffs are also more vitamin rich. So use them wisely and they'll pay you back, with interest!

About the author

Matt Jacks is a successful freelance copywriter who provides valuable tips and advice for consumers on a range of topics including weight loss. His numerous articles offer moneysaving tips and valuable insight on typically confusing topics.

This edited version of ‘How vitamins work' is reprinted with permission.

© 2004 - Freelancers-wanted.com.

Glucosamine

• Introduction
• How does it work?
• What is it used for?
• What is the evidence?
• Potential problems
• Conclusion
• Explanation of terms

Introduction

Glucosamine has become increasingly popular as a supplement due to its reported effect in osteoarthritis. Commercial products include: Aflexa (McNeil Consumer); Natures Blend Glucosamine (National Vitamin Co.); GS-500 (Enzymatic Therapy); Glucosamine Complex (Schiff); and others. Some are synthetically manufactured while others are derived from marine exoskeletons. The usual dose is 500 milligram three times per day; however always check the instructions before you take any supplements.

How does it work?

No studies have demonstrated exactly how glucosamine supplements works. All explanations of the mechanism of action are speculative, based on the natural function of glucosamine in the body. Glucosamine is one of the molecules making up glucosaminoglycans and these in turn make up the proteoglycans. Proteoglycans in different forms make up cartilage in bones and joints and it is thought that the breakdown of these proteins cause joint degeneration and osteoarthritis. Theoretically, if you supply glucosamine to the body, you help restore these molecules.

What is it used for?

The main use is in people that have established osteoarthritis and the aim is to relieve joint pain and to attempt to prevent further damage. The effects in healthy people with no joint problems have not been studied.

What is the evidence?

In a recent meta-analysis assessing the efficacy of glucosamine in treating symptoms of osteoarthritis, 13 randomised clinical trials compared glucosamine to a placebo (dummy drug); glucosamine was found to be superior in all except 1, using a variety of outcomes including patient reports of pain and mobility. In the four randomised clinical trials in which glucosamine was compared to a non-steroidal anti-inflammatory drug (NSAID), glucosamine was superior in two, and equivalent in two, again using the same outcomes. These studies have been small and subjective; therefore some experts in the field feel that further research needs to be done to prove the effect of these supplements. These trials are now underway.

Potential problems

Other than allergic reactions to the shellfish component, glucosamine appears to be safe. In most countries glucosamine is sold as a dietary supplement, so safety and formulation is solely the responsibility of the manufacturer.

Conclusion

There is evidence that this supplement works. I would therefore recommend it to anyone who has joint pains. However always see your doctor prior to starting any supplement as joint pains can be a sign of a more serious medical problem.

Explanation of terms:

Exoskeleton: the skeleton is on the outside, such as the lobster.

Meta-analysis: combines the results of several studies that address a set of related research hypotheses.

Osteoarthritis: this is medically a complex disease that affects joints in the body. It is thought of as a ‘wear and tear' disease of the joint. Cartilage in the joints is worn away resulting in pain and limitation to mobility.

Randomised clinical trial: the basic idea is that treatments are allocated to subjects at random. This ensures that the different treatment groups are 'statistically equivalent'.

References

http://en.wikipedia.org/wiki/Glucosamine

http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/glu_0122.shtml

Towheed TE, Anastassiades TP, Shea B, et al. Glucosamine therapy for treating osteoarthritis (Cochrane Review). Cochrane Database Syst Rev. 2001;1. 

Chondroitin sulfate

• Introduction
• How does it work?
• What is it used for?
• What is the evidence?
• Potential problems
• Conclusion
• Explanation of terms

Introduction

Available from numerous manufacturers as generic compounds: branded products include Ramott (Key Company); Chondroitin Sulfate Support (Natural Treasures); CSA (Twinlab); and Chonflex (American Health). Similar in action and usage as glucosamine, and in many instances are used in combination. Depending on brand and manufacturer supplements are made from extracts of cattle (trachea), pig (ear and nose), shark, fish or bird cartilage. The dose is around 400milligram taken 3 times per day. Always check manufacturer's instructions prior to taking any supplement.

How does it work?

No studies have demonstrated exactly how chondroitin sulfate supplements works. All explanations of the mechanism of action are speculative, based on the natural function of chondroitin sulfate in the body. Chondroitin sulfate is one of the molecules making up glucosaminoglycans and these in turn make up the proteoglycans. Proteoglycans in different forms make up cartilage in bones and joints. Chondroitin sulfate is an important structural component of cartilage and provides much of its resistance to compression. It is thought that breakdown of these proteins cause joint degeneration and osteoarthritis. Theoretically if you supply chondroitin sulfate to the body, you will help restore these molecules.

What is it used for?

Chondroitin sulfate has a similar use to glucosamine. It is mainly used in osteoarthritis (OA) that is well established as an aid against pain and joint discomfort. Also used prophylactically to prevent further joint damage. There is some evidence that it also has some effect against atherosclerosis in heart disease.

What is the evidence?

Multiple studies have been done into the effect of these supplements; however most of the early studies have had questionable results. A review in JAMA (Journal of the American Medical Association) in 2000 concluded: ‘Trials of glucosamine and chondroitin preparations for OA symptoms demonstrate moderate to large effects, but quality issues and likely publication bias suggest that these effects are exaggerated. Nevertheless, some degree of efficacy appears probable for these preparations'. These preparations seem most effective if glucosamine and chondroitin sulfate is taken together. The effect seems best in patients with moderate-to-severe pain in their joints.

Potential problems

A variety of mild gastrointestinal symptoms such as stomach pain, nausea and diarrhea have been reported. No sulfa-allergic reactions or other allergic reactions have yet been reported.

Conclusion

As supplements go the evidence is moderately strong that these supplements have a real effect. There also seem to be limited side effects. I would therefore recommend their use for osteoarthritis. However always see you doctor prior to starting any supplement as joint pains can be a sign of a more serious medical problem.

Explanation of terms:

Exoskeleton: the skeleton is on the outside such as the lobster.

Meta-analysis: combines the results of several studies that address a set of related research hypotheses.

Osteoarthritis: this is medically a complex disease that affects joints in the body. It is thought of as a ‘wear and tear' disease of the joint. Cartilage in the joints is worn away resulting in pain and limitation to mobility.

Prophylactically: (Greek ‘prophylaktikos' to guard or prevent beforehand) refers to any medical or public health procedure whose purpose is to prevent, rather than treat or cure, disease.

Randomised clinical trial:  the basic idea is that treatments are allocated to subjects at random. This ensures that the different treatment groups are 'statistically equivalent'.

References

http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/cho_0071.shtml

http://en.wikipedia.org/wiki/Chondroitin_sulfate

McAlindon TE, LaValley MP, Gulin JP, Felson DT (2000). Glucosamine and Chondroitin for Treatment of Osteoarthritis: A Systematic Quality Assessment and Meta-analysis. JAMA 283: 1469-1475.

Vitamin D

• Introduction
• How does Vitamin D work?
• Calcium and phosphate absorption
• Cancer and mortality
• Vitamin D and diabetes
• Immunology
• What happens if you take too much Vitamin D?
• Sources of Vitamin D
• Conclusion
• References

Introduction 

Vitamin D is an exiting vitamin that has received renewed interest in the research community. Its mechanism of action is being unravelled and it has been shown to have effects not only on calcium absorption but also wider effects on the body including prevention of cancer.  In the last decade the sun safe message has been getting through to people, but as a side effect of this Vitamin D deficiency has now become more common.

Vitamin D was discovered by Professor Edward Mellanby (1884-1955) by comparing dogs that had been raised exclusively indoors (no exposure to sunlight or UV light) verses dogs raised outdoors.

Vitamin D is a group of vitamins that includes Vitamin D1 through to Vitamin D5. It has recently been discovered that vitamin D acts as a hormone in the body. Vitamin D3 (cholecalciferol) is the vitamin that is produced in animals. Vitamin D2 is produced in plants and is the vitamin that is present in most vitamin preparations. In humans there is no major difference between Vitamin D2 and D3.

There are two sources of vitamin D in the body; production in the skin and through the diet. UV light converts cholesterol in the skin into Vitamin D3. Vitamin D3 needs to be converted into an active form; activated Vitamin D3 (Calcitriol or 1, 25(OH)2D3 or 1, 25 dihydroxyvitamin D3) before it becomes biologically active.  Two steps are needed to activate vitamin D3, the first one occurs in the liver and the second one occurs in the kidney.

There are basically two different types of Vitamin D available on the market.  Vitamin D (inactive) which is the form found in most vitamin supplements and activated Vitamin D (calcitriol). Calcitriol is usually used to treat osteoporosis as well as some other specific medical conditions. There is controversy as to what is the optimum dose for vitamin D . The recommendation range is from 200IU/day to 1000IU/day.

How does Vitamin D work?

The most well know action of vitamin D is in calcium absorption and its effect on bone health. These actions have been known for more than 100 years. Vitamin D has also been discovered lately to have a range of other important actions.

Calcium and phosphate absorption

Vitamin D increases calcium and phosphate absorption and retention in the body. It does this by promoting uptake of calcium and phosphorus from the intestine, and preventing excretion of calcium from the kidneys. It has direct effects on the bone, but these effects are still being studied. In children Vitamin D deficiency leads to rickets (http://en.wikipedia.org/wiki/Rickets) and in the elderly it leads to osteoporosis.

Cancer and mortality

Much research has gone into looking at Vitamin D as a prophylaxis (prevention) for cancer. Studies have shown that vitamin supplementation decreases the risk of breast cancer, colon cancer, and prostate cancer. Vitamin D supplementation also decreases mortality from all causes.

Vitamin D and diabetes

There have been a number of studies showing that vitamin D deficiency is associated with diabetes (http://www.diabetesaustralia.com.au/). A deficiency of Vitamin D increases the risk of getting both diabetes type I and type II.  In people that already have diabetes, Vitamin D deficiency leads to poorer control of their blood sugar levels. 

Immunology

Vitamin D suppresses some cell mediated immune responses. There is a group of disorders where the immune system in the body attacks itself - these are referred to as autoimmune disorders (http://en.wikipedia.org/wiki/Autoimmune). Experimental and epidemiological data show that Vitamin D deficiency is associated with a number of diseases, including: type 1 diabetes, multiple sclerosis and immune arthritis.  On the other hand, Vitamin D can promote some types of immune responses and has been shown to make a difference in infections such as tuberculosis (http://en.wikipedia.org/wiki/Tuberculosis).

What happens if you take too much Vitamin D?

Taking too much Vitamin D can be dangerous in pregnancy. The resulting high calcium levels that may occur in the mother can cause problems in the baby.

Very high levels of vitamin D can cause:

• Hypercalcaemia (high calcium levels) with muscle weakness
• Apathy (lack of emotion)
• Headache
• Anorexia
• Nausea and vomiting
• Bone pain
• Ectopic calcification
• Proteinuria (protein in the urine)
• Hypertension and cardiac arrhythmias (heart problems and irregularities in heart beat)

Prolonged high calcium levels can lead to:

• Vascular calcification
• Nephrocalcinosis (increased calcium content of the kidneys)
• kidney problems

Sources of Vitamin D

It is a good idea to look at the nutrition facts panel on the packaging of the food that you are buying.

Some foods that are high in Vitamin D include:

• cod liver Oil
• salmon, cooked
• mackerel, cooked
• milk;  non-fat, reduced fat, whole and vitamin D fortified
• liver, beef, cooked, 100g: 30 IU
• Egg, 1 whole (vitamin D is present in the yolk): 25 IU

Conclusion

It is clear that most people could benefit from Vitamin D supplementation. This applies especially to the elderly and to people with limited sun exposure. Care should be taken if you are pregnant. There is still some debate about the optimum dose. The recommended daily dose is 200IU/day, but doses up to 1000IU/day can be recommended in deficiency or specific conditions. Please always contact your doctor if you are concerned with your health.

Article Created: 1 Dec, 2007

References:

1. Ryan PJ. Vitamin D therapy in clinical practice. One dose does not fit all. International Journal of Clinical Practice 2007 (Nov): 61(11): 1894-9.
2. Boonen S, Vanderschueren D, Haentjens P et al. Calcium and vitamin D in the prevention and treatment of osteoporosis-a clinical update. Journal of Internal Medicine 2006 (Jun); 259(6): 539-52.
3. Sioen I, Matthys C, De Backer G et al. Importance of seafood as nutrient source in the diet of Belgian adolescents. Journal of Human Nutrition & Dietetics 2007 (Dec): 20(6): 580-9.
4. Vijayakumar S, Boerner PS, Mehta RR et al. Clinical trials using chemopreventive vitamin D analogs in breast cancer. Cancer Journal 2006 (Nov-Dec); 12(6): 445-50.
5. Giovannucci E. The epidemiology of vitamin D and cancer incidence and mortality: a review (United States). Cancer Causes & Control 2005 (Mar); 16(2): 83-95.
6. Zittermann A. Schleithoff SS & Koerfer R. Vitamin D and vascular calcification. Current Opinion in Lipidology 2007 (Feb): 18(1): 41-6.
7. Tangpricha V. Vitamin D deficiency in the Southern United States. Southern Medical Journal 2007 (April): 100(4): 384-5.
8. Bikle DD. What is new in vitamin D: 2006-2007. Current Opinion in Rheumatology 2007 (July); 19(4): 383-8.
9. Jones G. Expanding role for vitamin D in chronic kidney disease: importance of blood 25-OH-D levels and extra-renal 1alpha-hydroxylase in the classical and non-classical actions of 1alpha,25-dihydroxyvitamin D(3). Seminars in Dialysis 2007 (Jul-Aug) 20(4): 316-24.
10. Kalueff AV & Tuohimaa P. Neurosteroid hormone vitamin D and its utility in clinical nutrition. Current Opinion in Clinical Nutrition & Metabolic Care 2007 (Jan); 10(1): 12-9.
11. Reichrath J. Vitamin D and the skin: an ancient friend, revisited. Experimental Dermatology 2007 (Jul): 16(7): 618-25.
12. Robinson JK. Sun exposure, sun protection, and vitamin D. JAMA 2005 (Sep 28); 294(12): 1541-3.