Facteurs génétiques, médicaments, âge, régimes et autres surutilisations

Genetic factors, drugs, age, diet and other overuse

Genetic factors:

Many genetic diseases lead to particular nutritional needs, such as, for example, phenylketonuria or so-called “vitamin-dependent” diseases, such as leukinosis or lactic acidosis rebalanced by high doses of thiamine (vitamin B1), Hartnup’s disease by high doses of nicotinamide (vitamin PP), homocystinuria or pyridoxin-dependent convulsions by high doses of vitamin B6, or carboxylase deficiencies by high doses of biotin.

Likewise erythropoietic protoporphyria, which requires very high doses of beta-carotene or certain myopathies.

Certain hereditary pathologies, such as primary hypomagnesemia, or hypokalaemic periodic paralysis, lead to greatly increased mineral requirements.

Genetic factors, drugs, age, diet and other overuseLarge proportions of the population carry genetic peculiarities which, without leading to acute pathology in the short term, very significantly increase the risk of pathology in the medium or long term. However, they also prove to be flexible through nutritional provisions. Certain dyslipidimias of familial origin, essential hypertension, insulin-dependent diabetes, but also, and what is still insufficiently known, heterozygous homocystinuria, associated with an elevation in the blood of homocysteine ​​and risks of ‘high early cardiovascular events, which is easily controlled by supplementation of vitamins B6, B9 and B12.

From 1 to 2% of the population carries heterozygous homocystinuria, 15% of a heat-labile form of MTHfolate reductase, which also elevates homocysteine. 18% of the French population carry the HLA B35 group, associated with a defect in cell retention of magnesium, which causes them an increased need not only for magnesium, but for a magnesium-fixing cofactor such as taurine.

In the absence of this compensation, the people concerned have an increased vulnerability to stress, but also a higher risk of degenerative pathologies linked to aging. We also know that there are genetic predispositions for many other pathologies, for example overweight, colon cancer, breast cancer, osteoporosis …

These risk factors can be identified by questioning: family history, personal history; by clinical examination, also knowing that certain phenotypes present increased risks, for example thin women with fair skin for osteoporosis; by biological and complementary examinations, for example assays of fasting glycemia, total cholesterol, Lp (a) – a risk factor for atherosclerosis and thrombosis of genetic origin and independent of cholesterol -, or densitometry bone.

Each type of risk factor corresponds to nutritional provisions and increased requirements for certain micronutrients.

For some of them, it is necessary to avoid or reduce the intake of certain nutrients, for example phenylalanine in phenylketonuria, salt in essential hypertension, or iron and vitamin C in hemochromatosis.

It is obvious that when we move from risk factors to diseases, nutritional provisions become all the more important, not only in order to cover the needs increased by the digestive or metabolic disorders associated with them, but also in order to compensate the multiple nutritional interferences generated by exploratory and therapeutic interventions


> We will come back to the anti-nutritional effects of drugs in module 10 (Nutritherapy for the elderly).


Drugs that inhibit micronutrient absorption

Drugs interfering with micronutrient metabolism

Drugs that increase urinary micronutrient excretion


Multiple factors, chronic or acute, can therefore combine, increasing the gap between needs and intakes and exacerbating micronutrient deficits.

With age, the number of pathologies and medications increases. The defense and adaptation systems against infectious agents, toxins, free radicals, stress require greater amounts of micronutrients, in particular antioxidant vitamins, vitamin B6, magnesium, zinc and selenium, while the capacities of absorption, synthesis, activation and metabolism are decreased. For example the ability to absorb vitamin B12 or magnesium, vitamin D from the skin, or the ability to metabolize acids gradually reduced with age.

However, the intake of micronutrients through food decreases further. This is explained by the reduction with age in the quantities consumed.

Between 18 and 50 years old the average calorie intake per day is:

  • 2,256 calories for men;
  • 1,736 calories for women.

From the age of 65, the average calorie intake per day is:

  • 1794 calories for men;
  • 1,513 calories for women.

The gap between micronutrient needs and intakes continues to widen with age.

Diets and other factors:

Other factors can also be added to the previous ones: climatic variations and adaptation to cold lead to increased needs for magnesium and fatty acids of the omega 3 series, and heat leads to more intense sweat losses in minerals.

But the quantitatively most important factor is undoubtedly at the level of the lack of information on food, inappropriate choices, especially related to the use of food as a source of well-being (the first request that is made to a food even before energy and nutritional intake), not to say psychotropic (carbohydrates, energy dense foods, chocolate, alcohol have serotonergic uplifting effects), to the extreme dietary imbalances , by eating disorders, such as anorexia, bulimia, and especially by the widespread practice of weight loss diets and the increasingly frequent vegetarian, vegan, macrobiotic, dissociated, or other diets …

By reducing caloric intake, weight loss diets worsen the deficit in all micronutrients. In addition, during weight loss, fat-soluble pollutants that have been trapped (pesticides, hormonal disruptors, drugs, anesthetics, etc.) are released into the blood, deplete detoxifying, antioxidant and restorative nutrients and can create major damage, contributing to the onset of great fatigue, fibromyalgia, inflammatory syndromes or even toxic hepatitis.

As for special diets, if they can increase the frequency of deficits in certain micronutrients, they can at the same time lead to higher intakes in certain others, by increasing the frequency of consumption of foods insufficiently consumed by the majority, which can bring benefits.

This is of course the case with a vegetarian diet, associated with higher intakes of fiber, antioxidants, polyphenols, magnesium and potassium, reduced in saturated fat, iron, sodium, which results in an average reduction of the risks by half. cardiovascular and cancer, but which worsens the risks of deficiency in zinc, iron (for women, pregnant women, rapidly growing children), vitamin D and B12.

Any particular diet should therefore be associated with an appropriate compensatory supplementation.

All in all, in a situation where almost the entire population does not receive through food the recommended intakes of several vitamins and minerals, a number of circumstances and factors, such as old age, pollution, risk factors, chronic diseases, or discontinuously – but sometimes continuously for some -, such as stress, the pill, diets, infection or another acute pathology, treatments, growth, pregnancy, sport, climate change, further widen the gap between inputs and needs.


It begins with the obligatory vitamin K intake at birth (a very insufficient measure because all the fat-soluble vitamins are in deficit: D, E, carotenoids …), and it ends with the centenarians and super-centenarians whose absorption capacities and metabolisms have changed considerably (for example the skin, atrophied, hardly makes any more vitamin D in the sun, the capacities of absorption of zinc, vitamins B9, B12 and E are reduced, etc…). Vegetarians and vegans need a general supplement containing bioavailable zinc and vitamin B12 even more than others.

And this also concerns all patients who consume drugs – when they are justified – who should systematically benefit from the appropriate supplementation to compensate for the antinutritional effects and the side effects caused by the worsening of the deficits, for example the fatigue and myopathies associated with depression of coenzyme Q10 by statins.

Author Jean-Paul Curtay


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