Latest Research on Vitamin C Absorption and Selenium Use

By: Michael Lam, MD, MPH

Vitamin C absorption and SeleniumIt was in June 21, 1999 that the possibility of counter-interactions between inorganic selenium and vitamin c absorption was raised in the Danish television news. Two days later in the Berlingske Tidende newspaper, similar reports were published about Vitamin C inhibiting the absorption of inorganic selenium in the body. The problem arises when selenium interacts with ascorbic acid, it can be reduced to elementary selenium, which the body cannot utilize. This has been shown in studies. However, the issue becomes more complex when the human element is added into the equation, and to date, there is a considerable lack of scientific literature on the subject.

It is advisable to take Multi-tabs at meal times so that the various vitamins and minerals – including selenium – are made an integral part of and spread within the food intake. Multi-tabs contain 50 micrograms of selenium in the form of natrium seleniumate and between 60 and 90 mg of ascorbic acid. This will therefore lower the local concentrations of Vitamin C and selenium and lessen the chances of them inter-reacting. Furthermore, selenium creates protective complexes with food components – for example with amino acids such as methionin and cystein. These are important factors for vitamin C absorption.

It has been shown in studies that 200 mg of ascorbic acid has no effect on natrium seleniumate (50g). On the other hand, it even appears to improve the bio-accessibility of selenium when ingested at meal times. There is no evidence that food factors have any influence on selenium absorption, an issue that should be looked into in further studies. However, when a large dose of ascorbic acid (1g) is taken together with selenium prior to a meal, then the selenium is not absorbed. The crucial difference lies in taking them at meal times, then will the ascorbic acid not affect the absorption of selenium.

On the topic of selenium absorption, it also appears that the nature of selenium itself makes a difference. Several studies have shown that organic selenium can be almost totally absorbed by the body whereas the inorganic one is variable, generally over 50%. Organic selenium is selenium that is incorporated in amino acids such as methionin (seleno-methionin) or cystein (seleno-cystein). The body thus recognizes the selenium as amino acids and since amino acids are almost totally absorbed by the body, it means that the organic selenium is also absorbed in a camouflaged fashion. It is important to be aware of this, since otherwise an inadvertent over-dosage of selenium could occur.

Based on the above, there are 2 main points about the selenium absorption issue:

  1. The assertion that selenium is absorbed badly when combined with ascorbic acid form, for example, Multi-tabs, is undocumented. On the contrary, it has been shown in surveys that ascorbic acid has no effect on the absorption of selenium. In large doses, ascorbic acid can reduce the absorption of selenium, but this can easily be countered by taking the 2 together at meal times.
  2. The fact that organic selenium is generally absorbed better than inorganic selenium has been documented in various studies. The absorption of inorganic selenium is, however, still in the range of 50% and above. Here, however, it should be noted that organic selenium, as selenium bound in amino acids, is absorbed by the body uncritically and in an unregulated fashion as it is recognised as an amino acid. It is prudent therefore to take caution here as there is always the danger of selenium over-dosage.

Selenium and Vitamin C Absorption

Selenium and Vitamin C absorptionThe topics of proper supplementation and vitamin C absorption are complex due to both the chemical complexity of nutritional supplements as well as the physiological complexity of the body’s uptake and absorption of nutrients. Humans have not had the opportunity to enhance their nutrition with supplements for very long in our history, and so nutritional supplementation remains an evolving science. What is known, however, is that supplementation is important to achieving the optimal level of health and that the highest level of vitamin C absorption, as well as other vitamins and nutrients, is essential to healthy living. .

The modern world comes with a set of challenges and stressors unfamiliar to our ancestors, and our bodies’ neuroendometabolic (NEM) stress response systems are not well equipped to deal with the new and different stressors we face. As a result, we must be attentive to both the lifestyle and nutritional choices we make in order to achieve the optimal level of function and health for our bodies. Make sure you do your research and learn how to properly achieve the right nutritional balance with diet and supplementation for your body.

Vitamin C absorption
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I have not yet, heard of any ordinary doctors in Sweden, who have dr Lam´s approach to "adrenal fatigue" or Thyroid disorders . I have had some unusual symptoms, such as over alert,not tired despite poor sleep. I´ve a long time suspected a Thyroid disorder, primarily due to a subclinical thyroidit in 1993. The "holy" TSH has been normal, then everything should be okey!? I did an hairmineralanalysis 3 months ago, which showed very high copperratio, which Ì`ve never heard of, and which explained why I did`nt have the overall feeling of fatigue, low pulse, etc. The analysis also showed a low thyroid and adrenal function. The analysis did of course recommend a battery of different vitamins and minerals. However, I`m very sensitive to iodine, selenium, chromium so I have to be my own doctor. (I know, this is not recommended) So far, I have done rather well (2 1/2 month) The side effects have mainly been moderate, although, when I started with thyroid medication, lowest dose, I was very nervous, especially because I`ve often had very rapid pulse (probably coppertoxicity) and palpitations earlier.... and I had 2 "bad" days, but now the pulse is normal ca 70/ min. I take my bloodpressure, temp, pulse and weight every day. I take a lot of supplements 3 times/day.(I´m a nurse ) Marie