Tag: antioxidants

Fruit and vegetable antioxidants could significantly reduce cancer risk

Admin

June 25,  2003

Eating sufficient fruit and vegetables to maintain antioxidant vitamin and mineral levels could reduce the risk of cancer and mortality in men, report researchers from the French health and medical institute Inserm.

An eight-year study found a 30 per cent reduction in cancers and 37 per cent reduction in mortality among men who received a daily antioxidant supplement compared to placebo. The researchers claim that the study, called SU.VI.MAX, is the first randomised trial to show that an adequate intake of vitamins and minerals from fruit and vegetables can reduce the risk of cancer.

The double-blind, placebo-controlled study tested the impact of a daily dose of antioxidants on 13000 healthy subjects. The dose included 6mg of beta-carotene, 120mg of vitamin C, 30mg of vitamin E, 100ug of selenium and 20mg of zinc. The 7886 women, aged 35 to 60 years old, and 5141 men, from 45 to 60 years old, were divided into two groups and followed up over an average of 7.5 years.

There was no difference between the two groups concerning heart disease, supporting other studies testing the effects of antioxidants on cardiovascular health, but cancer risk was reduced by 31 per cent among men. This included most cancers, especially digestive, respiratory and skin cancers.

The absence of such effects in women was not due to the different cancers they developed but rather their better state of health at baseline, explained the Inserm researchers.

Again, while risk of death was 37 per cent lower among men receiving the supplements, the same effect was not seen in women. The researchers also found a higher risk of cancer and heart disease among men with the lowest levels of beta-carotene. The lower the level of the nutrient, the higher the risk of disease. The team stressed however that the findings should support a nutritious diet with regular consumption of fruit and vegetables rather than supplements.

Use of antioxidant supplements was necessary to be able to compare to placebo, but they claim that this effect applies equally to nutrients found readily in plant foods. The results back nutrition advice to consume at least five portions of fruit and vegetables daily rather than relying on supplements, claim the researchers.

They add that the observed effect is likely weaker than would be seen from fruit and vegetables, which have additional nutrients not included in the supplement used in the study. Further, they pointed to fears that people taking supplements may eat less fruit and vegetables, calorie sources which often lead to reduction in consumption of fatty and sugary products.

Source: NutraIngredients.com

Press Release from the Danish Society for Orthomolecular Medicine (DSOM)

Per Larsen

November 12, 2002

The Danish Society for Orthomolecular Medicine (DSOM):
Rumours that antioxidants should have no general effect on secondary prevention of heart disease originates from The Heart Protection Study published in July 2002 in the magazine The Lancet. The study was financed by e.g. the pharmaceutical companies Merck & Co. and Roche Vitamins.

The purpose of the study was, among others, to investigate Merck’s cholesterol lowering drug Zocor’s effect on various parameters such as blood clots in the heart and heart disease, etc. The study included 20,536 high-risk patients – ie. patients with known cardiovascular disease or dispositions for this – eg. diabetes.

The patients were randomized to 4 groups, of which 5000 patients received 600 mg vitamin E, 250 mg Vitamin C and 20 mg betacarotene. 5000 patients received both Zocor and vitamins. 5000 patients received Zocor only and 5,000 patients served as a joint control group. This means that the part of the study containing the vitamin group plus a joint control group comprised 10,000 people and not 20,536 persons as stated elsewhere.

Not surprisingly, the main result of the study showed that Zocor had a positive effect even at very low cholesterol values, which undoubtedly significantly increases the indication range for Zocor.

However, there are several criticisms, apart from the fact that the number of trial participants is exaggerated:

  • Dosage of vitamin E and vitamin C are not proportional to each other. The two vitamins are closely linked in the antioxidant protection of the cell. If there is an excess of one vitamin, it can have a pro-oxidant effect.
  • One will usually not give more than 100 – 200 mg of Vitamin E. Vitamin C should be given several times a day or as a prolonged-release preparation.
  • Vitamin C, as a single dose in a dose of 250 mg will only have an effect for a few hours. The half-life of vitamin C is approx. 4 hours, i.e. that from a daily dose alone you can not expect an effect at all – rather the opposite.
  • Beta-carotene has previously been tried alone in a major trial for lung cancer and smokers. Here, it appeared that this vitamin had a prooxidant effect with a prevalence of lung cancer in smokers as a result. The Heart Protection Study has not been able to confirm such an effect of an incorrectly unbalanced dosage.

The results of the study also coincide with the results found in the HOPE study, namely that there was no secondary preventive effect when consuming individual vitamins.

  • You can not study the effect of individual vitamins on diseases that have taken decades to develop. Vitamins act as co-factors and as antioxidants, they are involved in a complicated interaction with the body’s own enzymatic antioxidants in a way that we do not yet fully understand.
  • Individual vitamins or random combinations of two or three individual vitamins should not be perceived as a medicine that cures a disorder in the traditional sense, but as a method that can strengthen the body’s own antioxidant defenses.
  • You cannot simplify and define 3 different vitamins in an illogical mutual dosage for antioxidants generally. The antioxidant system reduces oxidized molecules. This is done according to the thermodynamic laws. The individual steps in this process, of which there are many, depend on the redox potential of the individual molecule. For example, urate is part of this chain. Urate is not an antioxidant in the traditional sense in everyday speech but possesses antioxidant properties just like albumin. A generalization is therefore completely incorrect.
  • The individual may have several or individual nutrient deficiencies. It is therefore not correct to study the effect of individual vitamins on chronic diseases.

Only in the last year has it become common knowledge that a substance such as Homocysteine (indicator of low B vitamins) has the greatest significance for risk and heart disease.

The content of the B vitamins: B12, B6, and folic acid in our food has decreased significantly since the Danish Ministry of Food began systematic studies of these in 1993. Thus 24% to 50% of the male population is at risk of deficiency diseases. Despite the private Nutrition Council’s stubborn adherence to the opposite, the Ministry of Food, Agriculture and Fisheries in Denmark is aware of this, but states that they are simply keeping an eye on developments.

The iron content of e.g. oatmeal has been reduced by 10% within just the last 5 years. The website of the British Ministry of Agriculture reports a 50% drop in selenium intake compared to 1983 and today.

………………………

By: Per Tork Larsen, M.D., DSOM

(No references)

rum.ctsu.ox.ac.uk/~hps
www.heartprotectionstudy.com/heartprotection/heartprotection/index.jsp
www.akudoc.dk
www.iom.dk