Vitamin A is important for the overall development and maintenance of the body. Our body does not produce vitamin A on its own. It needs to be supplemented through diet; that's why it's called an essential vitamin.
The retina is the film screen, located at the very back of the eye. It contains two important cells that process the light entering our eyes.
The rod cells help us see in low light, while the cone cells help our color vision. The rod cells contain an important protein called rhodopsin, which moderates low light vision. A form of vitamin A called the retinal helps activate rhodopsin.
This is why a severe deficiency of vitamin A can cause night blindness.
Vitamin A is also crucial for maintaining skin integrity and forming new skin cells. Since vitamin A is an excellent antioxidant, including it in your diet every day can lower your risk for heart attack.
We all know that carrots are a good source of vitamin A. They are a rich source of a molecule called beta-carotene. Beta-carotene is a provitamin A. Provitamins are substances that are converted into active vitamins in the body.
Beta-carotene is what is responsible for the bright orange color of the carrot. All plants provide vitamin A in the form of beta-carotene, among other forms.
Vitamin A is present as retinol, a form of active vitamin A, in animal food sources. Now, the beta-carotene from plant sources must be converted to active vitamin A for it to be useful to the body.
Let’s see how that happens.
The structure of beta carotene resembles that of a dumbbell - two ring-like structures joined by a chain. This chain is cut in a particular way to give rise to two molecules of retinol, or active vitamin A. This cleavage happens in the liver.
Image: Cleavage of beta-carotene to retinol
Vitamin A in the body can be converted or interconverted into different formats. The retinol and retinal forms are interchangeable, while there’s only a one-way conversion from retinal to retinoic acid.
Image: Different forms of active vitamin A
The retinal form of vitamin A is absorbed by the intestinal villi along with fats. From there, it is transported to and stored in the liver. Whenever there's a requirement for vitamin A, retinal is released by the liver. It then binds to the specific retinol-binding protein, which serves as a carrier to transport it to various locations of the body.
The cleavage or the cutting of beta-carotene to form retinol is carried out by an enzyme called Beta Carotene Oxygenase or Monooxygenase. This enzyme is produced by the gene called BCMO1 or BCO1.
Every person has two copies of the BCMO1 gene. But, about 45 percent of the population carries at least one change or variation in the gene that reduces the enzyme activity. This results in a significantly impaired ability to convert beta-carotene into retinal.
Depending on which combination of variants someone has, beta-carotene conversion can be nearly 70 percent lower than its normal efficiency.
Vitamin A deficiency has serious health implications.
Knowing your BCMO1 gene status can help you gauge your genetic risk for vitamin A deficiency. This can be done through a genetic test.
Most genetic tests provide your DNA information in the form of a text file called the raw DNA data. This data may seem like Greek and Latin to you.
At Xcode Life, can help you interpret this data. All you have to do is upload your raw data and order a nutrition report. Xcode Life then analyzes your raw data in detail to provide you with comprehensive nutrition analysis, including information on your vitamin A requirements.
Vitamin E has gained popularity recently. The association between vitamin E and skin health is a key reason for its popularity.
Vitamin E is a fat-soluble nutrient. Both plant and animal sources are available:
Animal sources: fish and oysters, dairy products like butter and cheese, Plant sources: vegetable oils, nuts and seeds, and green vegetables like broccoli and spinach.
There are 8 different chemical forms of vitamin E found.
All of these have varied effects on the body. Out of these, alpha-tocopherol (α-tocopherol) is the most active form while gamma-tocopherol (γ-tocopherol) is the most common form found in foods consumed by North Americans.
Here are some of the significant functions of vitamin E:
Vitamin E as an antioxidant
Vitamin E is a proven anti-oxidant (substances that prevent oxidation). It helps prevent cell damage from free-radicals.
Free radicals are active molecules in the body that can harm the cells in the body and prevent the cells from staying healthy.
Free-radical damage is the most common reason for skin problems including aging of the skin, development of wrinkles, fine lines, and dark spots, and skin becoming loose and saggy.
Vitamin E in both dietary forms and topical forms (external application in the form of creams, gels, and serums) is beneficial for healthy skin.
Vitamin E and immunity - Vitamin E helps improve immune response and provide protection against various infections by keeping the immune cells healthy.
Vitamin E and lifestyle risks - Lifestyle risks like smoking, drinking, and UV exposure can harm the cells in the body. Vitamin E provides protection against these.
Vitamin E and degenerative diseases - Many studies have shown that taking the recommended amounts of vitamin E reduces the risk of developing diseases like cancer, high blood pressure, and coronary heart diseases. These promising early results are being further investigated.
The early 1900s was the time when some of the initial vitamins like vitamin A, B, C, and D were discovered. Scientists and biochemists were involved in intense research identifying what else these vitamins could and couldn’t do.
Herbert McLean Evans and Katherine Bishop were anatomists experimenting with rats at the University of California. They fed rats only milk and studied how the rats were progressing. While they found that the rats were growing healthier, they were not reproducing!
They tried modifying the diet and included some starch and animal fats. The female rats became pregnant but were unable to carry the pregnancy to full term.
That’s when they introduced lettuce as a part of the diet. Now they found that the rats got pregnant and delivered healthy babies.
It was then recorded that healthy and natural sources of food were important for fertility. A particular nutrient was extracted from lettuce and was named vitamin E in 1922.
Since the nutrient was related to fertility in rats, it was given a Greek name ‘Tocopherol’. In Greek, ‘toco’ meant birth, ‘pher’ meant carrying, and ‘ol’ referred to it being a chemical.
Upon consuming vitamin E rich foods or vitamin E supplements, it is absorbed in the body like any regular fat source that you eat. Vitamin E is absorbed by the small intestine and from here, it reaches the blood and is circulated around.
The liver absorbs most of the vitamin E from the blood. You should know that the liver only acts on alpha-tocopherol and converts it into a form that is usable by the cells in the body. All other types of vitamin E are sent (excreted) out.
The converted form of alpha-tocopherol is now sent out to the blood and reaches all the tissues and cells.
Excess vitamin E is stored in the adipose tissues (fat-storing tissues present in several locations in the body) just like how normal fat is stored and is used when needed.
The use of vitamin E in the cosmetics and skincare industry has become quite common. Every product in the market seems to have added vitamin E to it.
Are all of these actually beneficial?
No, says research.
Vitamin E needs to remain stable to be useful for your skin. Most generic skincare products use unstable vitamin E forms that get destroyed as soon as you expose the product to light and air.
Hence the products you religiously use may do nothing to your skin.
The next time you buy a vitamin E-enriched product, make sure the base nutrient used is an ester form of vitamin E (a type of compound produced from acids) that is more stable and is also easily absorbed by the skin.
You cannot get vitamin E toxicity by just consuming foods rich in vitamin E. You get it only when you consume excess supplements. Here is a list of maximum levels of vitamin E that your body can handle safely.
Vitamin E toxicity can lead to internal and external blood loss (hemorrhage). When you consume excess vitamin E supplements for a longer duration, the side effects get worse.
For normal healthy individuals, vitamin E deficiency is quite rare. These individuals can easily get their recommended values only from regular food that they eat.
If a person gets vitamin E deficient because of certain genetic and non-genetic reasons mentioned below, it can result in:
Genetically, few people can have higher levels of vitamin E in the body and a few others can have lower levels. You will have to plan your vitamin E intake based on your genetic design.
APOA5 gene - The APOA5 gene is responsible for producing (encoding) the Apolipoprotein A-V protein. This is important for transporting fats including vitamin E. There are two SNPs of this gene that alter the vitamin E needs in the body.
CYP4F2 gene - The CYP4F2 gene produces the CYP4F2 enzyme. This helps in breaking down vitamin E. A particular allele of the gene is known to result in higher levels of vitamin E in the body.
TTPA gene - The TTPA gene helps produce the alpha-tocopherol transfer protein. This helps in transferring vitamin E in the body. Few mutations of the TTPA gene can cause Ataxia with Vitamin E Deficiency (AVED). AVED is another very rare inherited disorder that can lead to vitamin E deficiency.
Here, the transfer protein required to process vitamin E into cell-usable forms is absent or doesn’t function right. AVED results in vitamin E deficiency and individuals with these mutations are likely to require more vitamin E than recommended levels.
MTTP gene - The MTTP gene is responsible for producing a particular type of protein called microsomal triglyceride. This protein, in turn, helps produce beta lipoproteins. Beta lipoproteins carry fats in the food you eat from the intestine to the blood. These also carry fat-soluble vitamins like vitamin E.
There are about 60 different mutations of the MTTP gene that cause a condition called abetalipoproteinemia.This is a very rare inherited disease that hinders dietary fat absorption in the body.
People with abetalipoproteinemia are likely to require more vitamin E levels. They will need large doses of vitamin E supplements (5-10 grams a day) to prevent getting vitamin E deficient.