Vitamin D against atherosclerosis

January 28, 2008

Vitamin D counteracts the development of atherosclerosis and prevents fatal complications of high blood pressure – but vitamin D deficiency is very widespread.

We are not done with vitamin D. More and more information is streaming in about this amazing substance, which is actually not a vitamin but a hormone created in skin exposed to sunlight.

Now we will look at vitamin D’s effects on the heart and circulation. It seems as though the risks of blood clots in the heart and the brain are far lower in people who get enough vitamin D, which is to say people who get more than most. This “vitamin” is especially effective at lowering the risk in people with high blood pressure.

This find appears in a recent report from Farmingham, a little town in Massachusetts where the health and lifestyles of thousands of people (and their descendents) has been registered since 1948 in order to find lifestyle related reasons for cardiovascular disease. The Farmingham study is, without a doubt, the most famous of its kind. When we today take for granted that exercise, healthy diet, and aspirin prevents cardiac death it is the Farmingham project that we should thank.

The report in question is on a part of the study involving 1,739 people aged 50 – 70 who were free of cardiovascular disease at the beginning of the study. From 1996 to 2000 their vitamin D status was measured with blood tests after which their health was monitored for an average of 5.4 years (up to 7.6 years). Who suffered blood clots?

Those who had the least vitamin D in the blood! After seven years blood clots in the heart or the brain (stroke) was registered in one in ten with vitamin D levels over 37 nmol/l, but in no less than one in four of those with levels under 37. After correcting for differences within the group such as age, sex, cholesterol levels, smoking, diabetes, and so on, the group with the highest vitamin D levels still had a cardiovascular risk 60 % less than that of the group with the lowest levels. If these numbers are right, vitamin D is more important for cardiovascular health than aspirin or cholesterol medicine.

Strong immune system
The beneficial effects of vitamin D seem to be even greater for those with high blood pressure, which is the most important cause of cardiovascular disease. Among participants with high blood pressure the risk for those with vitamin D levels over 37 was half that of those with levels under 37.

This result is similar to that of other studies which have shown that low vitamin D status and high blood pressure and clogged cardiac arteries are related. The Farmingham has an even stronger message: If you lack vitamin D you are at risk of a heart attack within the foreseeable future.

Does this mean that vitamin D prevents atherosclerosis? Yes, this seems to be the case. This fits in well with other known effects including: that vitamin D counteracts an important hormone (renin) which is responsible for raising blood pressure and that when heart cells which normally use vitamin D are prevented from using vitamin D (through genetic manipulation) in experiments on mice, blood pressure rises quickly.

Without eating fatty fish is you get almost no vitamin D from October to May. Deficiency is therefore very widespread. In a European study of teenage girls more than one out of every three had severe anemia (blood percent of under 25 nmol/l). Over 90% of these girls would have, if they lived in Farmingham, ended up in the study group with severe atherosclerosis.

How much vitamin D is it wise to take? There is no rule of thumb, but it should be considered that a typical vitamin pill contains 200 units whereas one out of every two adult Americans need 1,000 units in order to have an “acceptable” vitamin D status (which is a concentration of 75 nmol/l – most American researchers recommend 75 – 150 nmol/l). It is also understood that it is completely safe to take up to 2,000 units daily.

Luz Tavera-Mendoza and John White, two molecular biologists from the American McGill University have shown that vitamin D causes the skin and the immune system to form antibiotics (cathelicidin and more) which kill bacteria, including tuberculosis bacteria. This is probably the explanation for the earlier idea that it is possible to cure tuberculosis with sunlight. These two researchers have written an easy to read summery of recent research and even reveal what they take as supplements during the dark months.

Luz, who is a younger woman, takes 1,000 unites (25 micrograms).
John, who is a younger man, takes 4,000 units (100 micrograms).

By: Niels Hertz, MD

References:
1. Wang TJ et al. Vitamin D deficiency and risk of cardiovascular disease. Circulation 2008;117:000-000.
2. Tavera-Mendoza L, White J. Celle defences and the sunshine vitamin. Scientific American 2007 (11):36-44.

circ.ahajournals.org
www.sciam.com

Folic acid for stroke – and to remember

June 12, 2007

You must remember your folic acid, otherwise you forget it.
This sounds like nonsense, but its not.

Folic acid helps keep the brain in good shape, and if you don’t get enough you might have problems thinking clearly and remembering when you get older.

Folic acid is the vitamin that fertile women should take (0.4 mg per day) unless they are 100% sure that they will not become pregnant. Far from all do this, even though folic acid prevents children from being a lifelong invalids due to spinal chord herniation (spina bifida) and reduces the risk of cleft lip and palate! That it is preventative is so called new knowledge (1) which is to say that it was pointed out, but ignored, over twenty years ago.

But folic acid also helps the memory and thought ability. Who do we know this? The English neurologist Edward Reynolds demonstrated it 40 years ago in hi article in The Lancet. He showed that 26 epilepsy patients who suffered folic acid deficiency due to their medicine improved when they received folic acid (2). This has since been forgotten.

Now there are new studies. One had negative results. Its authors concluded that folic acid has no effect on cognitive function, which did not improve for study participants who received 0.4 mg folic acid daily (without vitamin B12, in which they were mildly deficient) (3).

There is a simple explanation for this: the only lasted 24 weeks. This is not long enough, which will be explained below, but first a couple of other results.

An issue of the American Journal of Clinical Nutrition from last February included an article which outlined that the more pronounced folic acid deficiency in elderly people, the poorer (statistically) their cognitive function. The likelihood of decreasing cognitive function was more than doubled in those with a deficiency of folic acid (4). There are many people with folic acid deficiency because folic acid is primarily found in liver and leafy vegetables, which many people push to the side if their plates.

20% fewer strokes
Lack of folic acid is shown roughly by finding increased blood levels of the substance, homocysteine. It is an amino acid which is poisonous to the blood vessels (among other things) and which is believed to lead to atherosclerosis, but that the body nonetheless creates. Normally it is neutralised in part by folic acid. If you lack folic acid, you homocysteine levels rise.

A link between lowered cognitive function and homocysteine has been shown in Sweden (5). There it was shown that elderly people with documented memory problems often had high levels of homocysteine. This was only true with the poor memory was found along with atherosclerosis, which homocysteine is believed to promote!

In addition, Dutch researchers recently showed in a randomised trail that a supplement of folic acid (o.8 mg daily) for 50 – 70 year olds not only reduced their levels of homocysteine, but also statistically improved the “brain functions which have a tendency to decline with age.” Memory, reaction time, and the ability to speak quickly and fluently were bettered. The study lasted for three years, which is a necessary time period (6).

If that is not enough, a comprehensive study of eight randomised studies has recently shown that the risk of stroke resulting from atherosclerosis generally is reduced by 20% when taking folic acid supplements. The studies which lasted longer than three years showed the best results. Participants who had already had a stroke were less protected and if those who were lucky enough to live in a country where food is enriched with folic acid (USA, Canada) showed fewer effects.

We should remember our folic acid. The daily dosage should be between 0.4 and 0.8 mg daily.

By: Vitality Council

 

References:
1. Bille C et al. Folic acid and birth malformations. BMJ 2007;334:433-34.
2. Reynolds E. Folate and aging. Lancet 2007;;369:1601.
3. Eussen SJ et al. Effect of oral vitamin B12 with or without folic acid on cognitive function in older people with mild vitamin B-12 deficiency: A randomized, placebo-controlled trial. Am J Clin Nutr 2006;84(2):361-70.
4. Haan M et al. Homocysteine, B-vitamins, and the incidence of dementia and cognitive impairment: Results from the Sacramento area latino study on aging. Am J Clin Nutr 2007;85:511-7.
5. Nilsson K et al. Plasma homocysteine is elevated in elderly patients with memory complaints and vascular disease. Dement Geriatr Cogn Discord 2007;23(5):321-6.
6. Durga J et al. Effect of 3-year folic acid supplementation on cognitive function in older adults in the FACIT trial: A randomised double blind controlled trial. The Lancet 2007;369:208-16.
7. Xiaobin Wang et al. Efficacy of folic acid supplementation in stroke prevention: a meta-analysis. The Lancet 2007;369:1876-82.

www.bmj.com
www.thelancet.com
www.ajcn.org