Tag: colon cancer

Vitamin D protects against colon cancer

Claus Hancke

January 26, 2010

A huge European study now confirms that vitamin D may lower the risk of colon cancer by 40%.

The Danish Vitality Council has in several previous newsletters refered to scientific studies showing that vitamin D may lower the risk of cancer, and we have even been urged by journalists to withdraw those statements. Fortunately we have not complied.

A few days ago British Medical Journal published the largest study ever of the link between diet and health, known as the EPIC study, and this is just one of many results, we will see in the near future from this huge study.
More than half a million mostly healthy people from ten European countries have been closely studied and followed over 10 years by researchers from across Europe.

Participants completed detailed dietary questionnaires, and they have been checked with blood tests to identify their nutritional status.

At the time of analysis 1,250 cases of colon cancer had occurred and after comparison with a healthy control group researchers found that those who were low in vitamin D in their blood had significantly higher risk for this type of cancer.

Unlike many other studies this is characterized by being a prospective study. Thus looking-forward from the start time, and based on a group of healthy people. The study also distinguishes itself by involving so many different countries, cultures and – not least – food cultures.

Vitamin D, we primarily get from the sun, and a little bit from the diet. Danes are not the most tenacious fish eaters and much of the fish we eat is farmed and therefore does not include the fatty acids and other substances, we think they contain.

So we’re back at sunlight as the main natural source of vitamin D.

However, some of our ancestors for inscrutable reasons have found reason to settle north of the Alps, and it leads to midday sun high enough in the sky to make enough vitamin D in the skin for only 3-4 months a year (providing we have enough cholesterol).

So we must therefore tend to sunbathing when the Sun is at its highest point, ie the middle of the day, without sunblock, and therefore only half an hour, so we do not risk burning.

If it gets too complicated, you can also just grab a vitamin D capsule as a supplement. It is perhaps a little easier, and it can be done the whole year.
The dosage is somewhat controversial and should ideally be measured in a blood sample, but most serious scientists recommend between 2,000 and 4,000 IU, equivalent to 50-100 micrograms daily.

It will take a long time before we again will see such a thorough, multi-national study including so many people over such a long period.

So it is not just any study. It has high validity and ought to push the critically low RDA-value we have today.

By: Vitality Council

 

Litterature:
Jenab, M. et al (2010). Association between pre-diagnostic circulating vitamin D concentration and risk of colorectal cancer in European populations: A nested case-control study BMJ, 340 (jan21 3)
Can be downloaded directly at: www.bmj.com/cgi/content/abstract/340/jan21_3/b5500

Calcium supplements with vitamin D against colon cancer?

Claus Hancke

February 18, 2006

A large study attempted to show whether or not calcium and vitamin D prevent colon cancer. It was a strange study, using low doses over a short period.

There are probably those who believe that the latest study on calcium and vitamin D shows that neither is good for anything. But we should hesitate before going to that extreme. One can also believe that the study was not suited to draw this conclusion. Or, as it is stated in a leading editorial in “The New England Journal of Medicine:” the conclusion should be interpreted in light of the study was complicated and in light of the probability that the doses of calcium and vitamin D were too low.

The debate regards the insidious and widespread cancers of the colon and rectum. Half of a group of 36,282 American women between the ages of 50 and 79 took part in a seven year study where they received daily supplements of 1,000 mg calcium and 400 units vitamin D to see if reduced their risk of these diseases. The supplements given are the same as two normal calcium and vitamin D vitamin tablets, which many take to strengthen their bones. After the seven years the researchers assessed the number of women who developed colon and rectum cancer. The result was disheartening: Whether the women received supplements or placebo had not effect on the risk.

There was a single positive find buried in the data. The women who had the least vitamin D in their blood during the study had with statistical certainty the greatest probability of developing colon cancer. This could indicate that vitamin D has a positive effect. There was also a tendency, but only a tendency, that these women had the greatest benefit from the supplements.

Quite a lot of things contribute to that this conclusion be taken with a grain of salt. This is partially due to that the study was very complex.

Possibly the most important objection is that it “only” lasted seven years. It is believed that colon cancer takes 10-20 years to develop before it is diagnosed. It the supplements prevent a new cancer from forming it is clear that for this reason no effects will be found as early as after seven years. This has been considered: Participants in the study will be monitored further for the next five years.

Strong objections
If the goal was to show a difference within the seven year period, those responsible should have at least ended the study by examining the intestines of all of the participants in order to find early cancer stages, or polyps. This did not occur. There was neither the money nor the resources necessary to do over 35,000 intestinal examinations. It was only possible to establish that the number of independently undertaken intestinal exams and the number of discovered cancers in the two groups were about the same. But maybe nothing more can be expected.

One confusing detail is that the study participants were allowed to continue taking the supplements that they had taken before the study along with the supplements that they received as a part of the study. On average they received 1,100 mg calcium and 350 units vitamin D, both close to the recommended dosages, before the study began. Many of them therefore must have received very large doses of calcium, over 2,000 mg, per day. Is it reasonable to guess that this is the reason for the slightly increased frequency of self-reported kidney stones? 2.4% of those who received supplements and 2.1% of those who received placebo, got kidney stones during the seven years.

Also, the average age was relatively low (62), which reduced the risk of cancer, and therefore weakened the study. It was further weakened by the fact that more than one out of four participants did not finish the study. Whether this dropout rate is because calcium pills can cause constipation is not considered in the article.

Just as important, the dose of vitamin D, as referred to in the editorial, may have been too low. Recently it has been estimated that about 1,000 units daily is necessary for most people in order to achieve any supposed cancer preventing effect. This amount of vitamin D (or more accurately 25-(OH)-vitamin D) is necessary to achieve a serum concentration of over 30 nano-grams per litre (75 nanomols per millilitre). Nevertheless, only a minority of the study participants received this amount.

What can be concluded from this? The editorial gives some suggestions for new studies. Much indicates that vitamin D, and maybe calcium, prevents cancer. But we still lack sufficient knowledge.

By: Vitality Council

References:
1. Wactawski-Wende J et al. Calcium plus vitamin D supplementation and the risk of colorectal cancer. N Engl J Med 2006;354:684-96.
2. Forman M C et al. Calcium plus vitamin D3 supplementation and colorectal cancer in women. N Engl J Med 2006;354:752-4.
3. Garland C F et al. The role of vitamin D in cancer prevention. Am J Publ Health 2006;96:9-18.

Vitamin B6 Acts Against Colon Cancer

Claus Hancke

June 14, 2005

Alcohol increases the risk of several types of cancer. This may be because alcohol disturbs certain essential metabolic processes. But vitamin B6 and folic acid appear to repair the damage caused by alcohol, thereby restoring those processes.

If you allow yourself 1-2 glasses of red wine a day, you probably prolong life and help yourself against arteriosclerosis. It is a known matter. At the same time, however, it increases the risk of breast cancer and colon cancer. It is also a known matter. Less well-known is that this disadvantage apparently can be eliminated with the B vitamins folic acid and vitamin B6. When alcohol is a cancer risk, it may be because alcohol interferes with the processes that the two vitamins are involved in.

About two years ago, it was discovered that alcohol does not appear to increase the risk of breast cancer in women who get enough folic acid. In 2004, something similar was found for colon cancer in a follow-up of about 500,000 men and women in several countries. In this study, the risk was increased by 30% if more than two alcoholic beverages were consumed daily, but it was not increased in those who got the most folic acid. The same result was found in a Swedish study of ovarian cancer.

Now a new Swedish study shows that the same applies to vitamin B6, also called pyridoxine. 61,433 women whose diets were examined in the years 1987-90 and again in 1997 were followed for an average of 14.8 years. During that period, 805 of the women developed colon cancer. The fifth of participants who got the most vitamin B6 had a one-third lower risk of colon cancer.

However, the protective effect of the vitamin was particularly strong in women who regularly consumed alcohol. If you had at least two alcoholic beverages a week and belonged in the fifth with the highest intake of B6 in your diet, you could enjoy a risk of colon cancer that was only a little over a quarter (28%) as high as if you had been in the fifth of participants with the lowest intake.

Vitamin B6, like folic acid and vitamin B12, plays a role in the so-called 1-carbon metabolism. This means that, among other things, it has the task of forming chemical groups (methyl groups) that contain only one carbon atom and are used in the construction of enzymes, the cells’ genetic material (DNA), etc.

These vitamins supply small parts for the organism’s various construction tasks. Alcohol disrupts this supply, which may be the explanation for why alcohol increases the risk of cancer – or part of the explanation. On the other hand, it seems that enhancing the 1-carbon metabolism with folic acid and vitamin B6 repairs the damage.

Good sources of vitamin B6 are meat, liver, kidney, yeast, whole grains (i.e. not wholemeal bread), nuts and green vegetables. Whole grains used to be a crucial source of vitamin B6, but the dehulling of all grains has meant that humans generally have significantly less vitamin B6 in their blood than, for example, livestock. It is difficult to get the recommended daily 1.7 mg in the diet.

Folic acid is found mainly in liver, green vegetables and yeast. In practice, the most important source is green vegetables. Few people get enough of them. Six a day is the rule.

The authors of the current study, conducted at Karolinska Hospital in Stockholm, understandably conclude that their findings may be significant for the prevention of colon cancer, both because many people use alcohol and because the population’s B6 status can be easily improved by, among other things, dietary changes and vitamin supplements.

By: Vitality Council

References:
1. Larsson SC, Giovannucci E, Wolk A. Vitamin B6 intake, alcohol consumption, and colorectal cancer: a longitudinal population-based cohort of women. Gastroenterology. 2005 Jun;128(7):1830-7.
2. Eunyoung Cho et al. Alcohol intake and colorectal cancer: A pooled analysis of 8 cohort studies. Annals of Internal Medicine 2004;140:603-13.

www.gastrojournal.org/scripts/om.dll/serve
www.annals.org
www.iom.dk

Magnesium May (Perhaps) Prevent Cancer

Claus Hancke

February 21, 2005

The less magnesium you get, the larger is the risk of colon cancer – plus asthma and imbalances in the muscle- and nerve function. Diuretic pills and empty calories is the major cause of magnesium deficiency.

Swedish researchers have discovered that a lack of magnesium seems to increase the risk of colon cancer which is one of the most common forms of cancer. The increased incidence was discovered in a group of 66,000 women of 40 – 70 years of age who were followed during a 3 year period.

The majority of the 66,000 women got less than the recommended 350 mg. of magnesium a day through their diet. Actually, if a woman got more than 255 mg. of magnesium a day, she would belong to the top 20% in regard to magnesium intake. This top 20% had a significantly reduced risk of colon cancer compared to the rest of the women, and the risk was inversely proportional to the intake of magnesium.

Why do so few people get enough magnesium? It should not be difficult to get enough, but it is estmated that at the beginning of the last century, an average adult person got more than 1000 mg. of magnesium a day. That is four times as much as the women who today get the most.

The explanation is obvious. At the beginning of the last century, the consumption of empty or half-empty calories in the form of sugar, margarine, and white flour was much smaller than it is today. In 100 g. of oatmeal, there is almost 300 mg. of magnesium while other whole grain products (and semisweet chocolate!) contain approx. 100 mg. of magnesium per 100 g. That is four times as much as in industrially manufactured white flour.

Lean meat which was rarely used 100 years ago does not contain more than about 25 mg. of magnesium per 100 g; which is about the same as in vegetables such as spinach, peas, and beans.

The comparison is interesting for other reasons than its relation to cancer. In numberous studies, a lack of magnesium has been linked to atherosclerosis and heart failure; diseases that were not all that common 100 years ago.

A number of years ago, for example, a Scottish study showed that when asthmatics were given a supplement of just 100 mg. magnesium, they suffered fewer asthmatic attacks and their mucous membranes were less irritable. It is a well-known fact that asthma is also a far more common disease today. The effect corresponds to the fact that you can stop an asthma attack by intravenously injecting magnesium sulphate.

Magnesium has many other effects as well: It inhitibs the tendency of the blood platelets to aggregate and increases the production of nitric oxide (NO) which keeps the blood vessels open, it lowers the blood pressure, and it maintains a normal circulation.

All these things can be assumed to reduce the risk of coronary thrombosis; a connection that is presumed but has yet to be finally confirmed. However, it is further supported by the fact that magnesium has several effects in common with the cholesterol-lowering drugs called statins – without having the side effects, that is.

The relaxing effect on the blood vessels might be connected to the generally relaxing effect on muscles and nerves for which magnesium is well-known. In earlier days, complete anaesthesia was induced by magnesium just as local anaesthesia can be achieved by injecting magnesium under the skin.

Magnesium is still the most important remedy against cramps in pre-eclampsia and can also be used against tetanus. Many people also benefit from a magnesium supplement that can relieve cramps in the legs which can be a nuisance to both pregnant women and elderly people.

It can seem alarming that we get so much less than we used to of a mineral with these properties. Not least because the widespread use of diuretics contribute to the lack of magnesium by excreting magnesium via the kidneys.

In addition to this, we can now add the possible anti-carcinogenic effects of magnesium. Of course, it might also be the result of a combination of other deficiencies which occurs at the same time as the magnesium deficiency. A poor diet will result in a lack of a number of essential nutrients, so the moral must be: Eat properly!

By: vitality Council

References:
“Magnesium Intake in Relation to Risk of Colorectal Cancer in Women”, Susanna C. Larsson, MSc; Leif Bergkvist, MD, PhD; Alicja Wolk, DMSc, JAMA. 2005;293:86-89.
“Comparison of Mechanism and Functional Effects of Magnesium and Statin Pharmaceuticals”, Rosanoff A, Seelig MS, J Am Coll Nutr, 2004;23(5):501S-505S. (Address:Mildred S. Seelig, MD, E-mail: mgseelig(at)comcast.net ).
Ford Es, Mokdad AH. Dietary magnesium intake in a national sample of US adults. J Nutr 2003;133:2879-82
Goodman and Gilman’s The Pharmacological basis of therapeutics. Pergamon Press 1990. P. 704-6.

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www.nutrition.org
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