The Importance of Vitamin Intake for Nutrition, Fitness and Human Health

By Friedrich Reuss, Egloffstein

Vitamins are organic substances that have a catalytic function in the biochemical reactions of the body’s metabolism. They must be taken in from the outside and are not the body’s own building blocks (otherwise, amino acids would also be considered vitamins).

The classic idea is that a deficiency of a vitamin quickly leads to a reduction in the biochemical reactions concerned and eventually to the breakdown of the body.

A Severe Vitamin Deficiency Is Not Compatible with Life in the Long Term

Under this line of thinking, vitamin researchers have long believed that they could quickly and safely determine the vitamin requirements of humans with experiments that create an artificial vitamin deficiency. The first uncertainties of the method arose from the fact that tolerance to a borderline supply of vitamins is determined very differently in people. This is apparently dependent on genetic factors (including absorption), on the presence and availability of other nutrients and on current metabolic events.

It was later recognised that most vitamins control a variety of biochemical reactions and that different amounts of vitamins are sufficient for their function. Thus, the experimentally determined vitamin requirement of humans depends on the metabolic function, which is used as a yardstick here.

In this situation, it is clear that the vitamin requirement of humans ultimately depends on the biochemical function that requires the highest supply of a vitamin. This sounds simple, but it is very consequential, because no one can assume that we already know all the functions of a vitamin. It is more likely that the opposite is true, namely that we do not yet know all the functions controlled by most vitamins.

A typical example is vitamin K, which used to be seen only as a coagulation vitamin and for which a vitamin requirement of about 40-80 µg per day was then assumed. Today we know that vitamin K also plays a very important role in the synthesis or remodelling of collagen and bone substance. For this function, however, obviously much higher vitamin intakes are optimal – the discussion currently ranges between 250 and 1,000 µg (amounts that can certainly be achieved with green vegetables).

A similar example is vitamin C, where apparently very low amounts (20-40 mg) are sufficient to maintain collagen synthesis in humans. For antioxidant cell protection, however, much higher intakes are required (around between 200 and 1,000 mg) and here we are still in the phase of dose optimisation.

Effects of Vitamin Deficiency.

Some vitamin effects take place in secret, so to speak, and the difference between a good and a poor vitamin supply only becomes visible after months, years or even decades. These are time periods that go far beyond the time frame of earlier vitamin studies. Precise new scientific findings can only be expected here after a long time. Especially in the case of vitamins with antioxidant effects, studies to find an optimal supply are difficult because damage caused by insufficient vitamin supply often only becomes visible after decades.

Although the biochemist or laboratory physician can estimate the antioxidative cell protection from some laboratory values, the influence on long-term health can only be reliably assessed and quantified under real time conditions.

The situation is similar with vitamin effects, which are supposed to ensure cancer protection or the maintenance of an efficient immune system in healthy individuals.

In this situation, the highly ethical health policy question arises whether one should wait until, for example, the cancer protection by antioxidant nutrients has been precisely measured, or whether one should already raise the vitamin recommendations when the positive trend is assured without any known harmful effect. This is the core question we currently have, especially with antioxidant vitamins.

We know that a much higher intake than the previously recommended basic intake reduces the risk of many diseases. Nevertheless, the authorities in some countries refuse to recognise higher vitamin intakes as nutrition. Apparently, many millions of people still have to die from diseases of civilisation until such good statistical data are available that the authorities and national nutrition societies will significantly raise vitamin consumption recommendations.

Of course, vitamin doses should be such that no harm can come to humans even under unfavourable circumstances. Decades of experience in the use of food supplements in countries with “liberal food laws” have shown that serious undesirable vitamin effects are extremely rare. If intoxications were known at all, they were due to blatant misuse or gross misdosing of critical vitamins by the manufacturer. It was soon realised that only vitamins A and D pose a certain risk, because the safety factor between recommended intake and possible adverse dose is less than 10. However, more recent scientific findings have largely given the all-clear here too: Today, vitamin A is no longer considered to be embryotoxic to any great extent, and vitamin D is also harmless up to relatively high and usually unnecessarily high doses according to the current state of knowledge. The severe restriction of food supplementation with vitamins A and D in Germany has therefore long been scientifically outdated, yet the German authorities are not rethinking this. Only the constraints imposed by EU law will initiate a normalisation here.

Official Recommendations – Optimal Intake?

Simplified, we can say today that the B vitamins, vitamin C and vitamin E are safe up to 100 times the official basic recommendation, and vitamins A and K up to 10 times and vitamin D at least up to 5 times.

So we can use the modern vitamin dosages without relevant risks. However, it is always wise to use the vitamins in reasonable combination and not to consume a single vitamin in extreme doses. In this context, it is important to know that even the good antioxidant vitamins can become pro-oxidant when taken in excessive doses – if taken individually. The combination of antioxidant vitamins with each other and with antioxidant secondary plant substances eliminates the prooxidant risk with a high degree of certainty, so that food law quantity limits are not justified for the nutrients mentioned.

A new way to approach optimal vitamin intake is through stone-age nutrition research. Here, various research groups around the world have gathered findings on the diet of our ancestors. With all the diversity due to climatic and regional differences, it can be said that our ancestors consumed up to 10 times as much vitamins (and other micronutrients) as the current official recommendations say. For more details, see my article on Stone Age nutrition.

Dietary Trends Over the Last 100 Years

The modern diet has become considerably poorer in vitamins, especially in the last 100 years: Increased agricultural yields have resulted in lower vitamin densities and industrial processing and storage have robbed food of much of its vitamins. A typical example is cereals: the germ, which is rich in vitamins, is removed during milling, at times even the remnants of vitamin B2 have been bleached away, the flour has been depleted of vitamins through long storage times under the pretext of improved baking quality, and the last traces of vitamins have finally been further reduced through cooking and baking. The last 100 years of the food industry were a time of progressive food destruction and a consistent path to the programmed early death of the unsuspecting consumer. Only the idea of reformed nutrition and today organic nutrition have led to a slow rethinking. But anyone who has eaten low-quality, vitamin-depleted food for 50 years, for example, has probably forfeited many possible years of a healthy life. This can hardly be reversed even with expensive and high-dose food supplements.

Our Possibilities Today

Biologically, according to today’s knowledge, man is quite capable of living 100-120 years in good health if he optimizes his lifestyle, diet and especially his vitamin intake. A philosopher would have to say “The art of living is to grow old in good health and die without disease if possible.” (A truly provocative idea for many business circles that are currently earning money from the German “disease system”!) With optimal nutrition or vitamin supply and a sensible lifestyle (avoiding stress and moderate physical activity), this is achievable for most people! We only have to want it consistently and also enforce the political conditions for it. European citizens have a legal right to healthy nutrition and sensible dietary supplementation and must demand this from both politicians. On the nourishing societies steered by scientific perseverance, industrial interests and self-interest here obviously no reliance is! (See here the own article to the correction of the nutrient recommendations of the DGE in the year 2000!)


About Our Guest Author Friedrich Reuss

Friedrich Reuss graduated in chemistry from the University of Münster in 1966. He then worked as a research assistant at the Institute of Organic Chemistry and was active in the department of Prof. Dyong in the field of bioactive plant sugars. After working as a chemistry teacher, Friedrich Reuss worked for almost 25 years as a scientific employee in a well-known pharmaceutical company. His main focus was the research of artificial nutrition as well as the investigation of amino acids, vitamins, minerals, trace elements, carnitines, taurines and glutathione.

Since 1993, he has been an officially appointed expert of the Nuremberg Chamber of Industry and Commerce with a focus on special foods such as dietary supplements and sports nutrition. Since 2013, he has also been an appointed expert for the Suhl/Thuringia Chamber of Industry and Commerce. Within the last 25 years he has supervised the approval of at least 500 food supplements. His expert opinions influenced not only many decisions of the German Supreme Court, but also those of the European Court of Justice.

He is the author of numerous scientific publications and a book on the nutritional importance of glutathione for cells and immunity.