Vitamins
A New Vitamin A Discovered
Scientists recently discovered vitamin A5, challenging our understanding of this essential nutrient. Learn why eating both plant and animal foods matters for your health.
Vitamins
Scientists recently discovered vitamin A5, challenging our understanding of this essential nutrient. Learn why eating both plant and animal foods matters for your health.
Line items
β-Carotene (provitamin A) is certainly not a suitable source of vitamin A for people, particularly for pregnant women or women planning to become pregnant.
We discuss this in detail in our article, "[source no longer available]". We also explain why retinol—that is, vitamin A—in conventional doses is not dangerous during early pregnancy.
The background is that warnings about vitamin A consumption or supplementation during pregnancy are very common! This is reckless, because first, adequate vitamin A intake is far from guaranteed in many women, and second, a lack of vitamin A is also teratogenic, meaning it can harm the developing embryo.
Vitamin A is generally a fascinating topic. It contains far more complexity and interesting information than is commonly assumed.
For all of us—and especially for the embryo—vitamin A is so important because it is converted into a hormone called retinoic acid, which has its own nuclear receptor. Yes, exactly: it binds to a receptor directly on DNA, where it regulates important genes and thus important physiological processes.
These include blood cell formation (erythropoiesis), iron transport, myelin synthesis in the central nervous system, wound healing, function of (mucous) membranes, antibody formation, and—as mentioned—embryogenesis (maturation of muscles, the nervous system, formation of various organs, etc.).
All of this starts with the so-called retinoic acid receptor (abbreviated: RAR)—and thus with retinol (vitamin A), which is converted to retinoic acid. So far, so good.
But there is another receptor that can be activated by retinoic acid—namely the retinoid X receptor (abbreviated: RXR). This interests us because it's precisely this receptor that binds to the vitamin D receptor, allowing vitamin D to work at all.
This is why we have long pointed out that vitamin D also needs vitamin A to function. Actually correct. Only apparently not completely accurate—once again.
When we speak of retinol, we're also speaking of vitamin A1. This is essential for us because it activates the aforementioned RAR. What many don't know: there is also a vitamin A2, found for example in cod liver oil, which can also bind to the RAR.
We're talking about dehydroretinol. When there are multiple forms of the same vitamin, we speak of vitamers. Vitamin A2 is such an A-vitamer that can partially take over the functions of vitamin A1 (retinol) and has a similar bioactivity.
But that's not all. In the animal kingdom, vitamin A3 and A4 also occur. But they have no biological effect in the body. And then came…
Vitamin A5—brand new. This knowledge is five years old. Researchers [source no longer available] that vitamin A1, that is, retinol, is not actually a good precursor for activating retinoid X receptors—those nuclear receptors that influence, for example, vitamin D activity.
Instead, they demonstrated in their work that 9-cis-β-carotene (9CBC) and 9-cis-retinol (9CROL) are the precursor substances for a hormone that activates those RXR receptors.
This is so crucial because what appears to be a newly discovered vitamin has been found, since the body cannot produce these two substances on its own. These (pro)vitamins are also found in food—both as carotenoids in plants and in vitamin A-rich animal foods.
This would be the first newly discovered vitamin since vitamin B12 in 1948.
What are we trying to say? You should eat. Both plants and animals. Just as every human before us had to do for thousands of years in order to avoid nutritional deficiency diseases.
Today we have what seems like the luxury of being able to choose exactly how we want to eat. In reality, however, this creates many problems, because nutrition, like everything else in life, is enormously complex when you look closely at it.
One can't help but smile when someone tries to derive "good nutrition" from approximately 40-50 known essential nutrients.
The truth is: we know at most a fraction of the bioactivity of our food. It's possible that there are 60, 70, or 80 nutrients that have a not-yet-described essentiality for us humans—nutrients we absolutely need in order to be and remain healthy, fit, vital, psychologically stable, and physically robust.
So…
Therefore: Eat. Please a mix of animal and plant. It doesn't have to be much. With any other form of diet, we run the risk of speculating ourselves and literally eating ourselves sick.
