Vitamin A

First discovered in 1919, and by 1924 it had been broken down and separated from its natural whole food complex: “purified.” By 1931, LaRoche – one of the largest pharmaceutical companies in the world, even today – had succeeded in “synthesizing” vitamin A – a purely chemical copy of a fraction of naturally occurring vitamin A known as retinoic acid. Isolated, it cannot perform its biological functions. Taken as a synthetic, it must then draw on a list of resources already in the body in order to complete its make-up. Whole food vitamin A, by contrast, is already complete and ready to go. It is necessary for good eyesight, DNA synthesis, and protects cells from free radicals. A study reported in Apr 94 in the NEJM of some 30,000 Finnish subjects showed conclusively that synthetic vitamin A had no antioxidant effect whatsoever.

A true antioxidant helps to protect heart muscle, lungs, and artery surfaces from breaking down prematurely. In the aforementioned Apr 94 NEJM study of 30,000 Finnish subjects that showed conclusively that synthetic vitamin A had no antioxidant effect whatsoever, the subjects who received the synthetic beta carotene actually had an 8% higher incidence of fatal heart attacks, strokes, and lung cancer than those who got the placebo (sugar pill). Stands to reason: the synthetic brought no vitamin activity to the tissues that needed it. As a dead, purified chemical introduced into the body, the synthetic further stressed the immune system, the liver, and the kidneys which all had to try to break down this odd chemical and remove it from the body. It would be bad enough if they were harmless, but synthetic vitamins actually have a net negative effect.

Most synthetic vitamin A consists only of retinal, retinol, or retinoic acid. The well-publicized potential for toxicity with mega doses of vitamin A involves one of these three. Vitamin A toxicity, known as hypervitaminosis, always results from an excess of synthetic, “purified” vitamin A, and never from whole food vitamin A. (DeCava, p 86) Effects of vitamin A toxicity include tumor enhancement; joint disorders (such as osteoporosis); extreme dryness of eyes, mouth and skin;  enlargement of liver and spleen; immune depression; and birth defects.

Beta Carotene

— is a precursor the body can convert to vitamin A. Unfortunately, as a supplement, synthetic beta carotene is usually “stabilized” in refined vegetable oils. In this trans fatty acid form, oxidation occurs and the chemically “pure” beta carotene can no longer act as a nutrient, because it was changed. Almost all synthetic beta carotene is produced by the Swiss drug giant Hoffman-LaRoche. This form can no longer be converted to vitamin A. The best it can be is worthless, and at the worst is toxic.

Natural vitamin A and beta carotene are well known as immune boosters and cancer fighters, in their role as antioxidants. Synthetic vitamin A by contrast has actually brought about significant increases in cancer. A study done in Finland provided smokers with large doses of synthetic beta carotene. Lung cancer incidence increased 18%! (NEJM Apr 94, “The Alpha Tocopherol Beta Carotene Cancer Prevention Study Group”) These findings were corroborated two years later in another study written up in Lancet. Pharmacologic doses of syntheric beta carotenes were found to block the antioxidant activity of the other 50 naturally occurring carotenoids in the diet. Anti-cancer activity was thus blocked by the synthetic. (Lancet, 1996)

With the vast outpouring of wrong information about vitamins A and C, the findings of a 1991 article in Health Counselor are no surprise: 50% of Americans are deficient in vitamin A and 41% are deficient in vitamin C. Synthetic vitamins cannot prevent deficiencies.

The National Institutes of Health’s global database of peer-reviewed medical literature, PubMed, turns up 52,337 articles on vitamin A. A sampling of those articles indicates a wealth of beneficial effects associated with this micronutrient. The journal Nutrients discusses the positive effects of vitamin A on the immune system, extending to reduced mortality associated with diarrhea, measles, meningitis, and other illnesses endemic to third-world populations. The Journal of Molecular Neuroscience details multiple pathways of action for vitamin A for treating multiple sclerosis. A Lancet study demonstrates reduced incidence of malaria among children treated with vitamin A supplementation in Papua New Guinea. Vitamin A also protects against night blindness, protects against age-related macular degeneration, aids in bone and tooth development, and has a protective effect against squamous cell carcinoma.

Vitamin A is fat-soluble, a powerful antioxidant, and part of a family of compounds that are vitally important to the body. It supports the immune system, helps strengthen vision, assists with normal organ function, reproduction, and more. ^[1] It works synergistically with a number of other vitamins and minerals, including vitamins D, K2, zinc, and magnesium, without which it cannot perform its functions.

Vitamins are important for maintaining good health and if you don’t get what you need, vitamin deficiencies and health problems can result. Many people take a multivitamin as a precaution, some do not.

How can you get enough vitamin A and what are the overall health benefits?

Basic Forms of Vitamin A

“Vitamin A” actually refers to several different but related nutrients that can be divided up into two main categories:

1. Retinoids – This class of compounds plays an important role for healthy vision, cell and bone tissue growth, and immune function. And it’s because of that they’re often used in medicine. However, vitamin A in this form can only be found naturally in animal products like liver, eggs, and milk, so vegetarians and (especially) vegans need to be aware of where they’re getting their vitamin A.
2. Carotenoids – In contrast, carotenoids like beta-carotene are found in plant sources like vegetables and fruits. Like retinoids, carotenoids can also help maintain healthy skin, eyes, and boost the immune system. ^{[2] [3]} Carotenoids like the one found in kale, carrots, and other vegetables have to be converted into a usable form of vitamin A (retinol) by the body. ^[4]

The only type of vitamin A your body can readily use is retinol, found in animal foods like liver and eggs. When you get carotenoids (pre-vitamin A) from plant sources, your body must convert the carotenoids into bioavailable retinol. If you’re in perfect health this should not pose a major problem, however, a number of factors can inhibit your body’s ability to absorb carotenoids and convert them into retinol (Vitamin A). This includes genetics, digestive problems, alcohol use, certain medicines, toxic exposures, and medical conditions that interfere with the digestion of fat (including Crohn’s disease, cystic fibrosis, pancreatic enzyme deficiency, and gallbladder and liver disease).

In a majority of people, the carotene-to-retinol conversion is severely compromised, and in some it may be quite negligible. This is particularly true for infants, diabetics, and those with compromised bile production.

Your body’s ability to convert carotenoids into bioavailable vitamin A also depends on your diet in general. If you’re on a low-fat diet, your conversion rate is virtually guaranteed to be inadequate.

While carotenoids are water-soluble, you still need healthy fats to promote efficient conversion of carotenoids to retinol. As explained in one 2004 study:

“[P]rovitamin A carotenoids are converted to retinal by beta-carotene-15,15′-dioxygenase. The enzyme activity is expressed specifically in intestinal epithelium and in liver.

The intestinal enzyme not only plays an important role in providing animals with vitamin A, but also determines whether provitamin A carotenoids are converted to vitamin A or circulated in the body as intact carotenoids.

We have found that a high fat diet enhanced the beta-carotene dioxygenase activity together with the cellular retinol binding protein type II level in rat intestines…

Thus, the bioavailability of dietary provitamin A carotenoids might be modulated by the other food components ingested.” [Emphasis mine]

Many associate vitamin A with beta-carotene alone, and believe as long as they eat plenty of sweet potatoes and carrots, they’re getting enough vitamin A. But if your body cannot properly convert carotenoids into retinol, you might still end up with a deficiency if you shun all animal foods. Retinoids and carotenoids — which are both part of the umbrella term “vitamin A” — are chemically different, and therefore provide different types of health benefits; some of which are better known than others.

The following list illustrates the relationship between the different vitamin As, along with some of their health benefits.

1. Retinoids (fat-soluble, biologically active vitamin A found in animal foods)

• Retinol: Bioactive form of vitamin A, which is converted into retinal, retinoic acid, and retinyl esters
• Retinal: Vision health and healthy growth
• Retinoic acid: Skin health, tooth remineralization, bone growth
• Retinyl esters: Biologically inactive storage form

2. Carotenoids (water-soluble pro-vitamins found in plant foods)

• Carotenes
  • Alpha-carotene: Antioxidant with potential anti-cancer activity; stimulates intercellular communication
  • Beta-carotene: Most efficiently converted into bioactive retinol. (Beta-carotene should be avoided in supplement form though, as studies have linked it to increased cancer risk. Beta carotene from whole food is safe, as your body will only convert what it needs into retinol)
  • Gamma-carotene
  • Delta-carotene
  • Epsilon-carotene
  • Zeta-carotene

• Xanthophylls
  • Astaxanthin: High-potency antioxidant with anti-inflammatory properties, shown to benefit rheumatoid arthritis; athletic performance; heart- and brain health; age-related macular degeneration. Also protects cells from UV radiation
  • Beta-cryptoxanthin: Antioxidant with anti-cancer activity. Studies show it may reduce risk of lung- and colon cancer by 30 percent, and rheumatoid arthritis by 41 percent
  • Canthaxanthin: Sometimes used in artificial tanning products, canthaxanthin  may help reduce photosensitivity  associated with erythropoietic protoporphyria, a genetic disorder
  • Fucoxanthin: A brown seaweed pigment that appears to stimulate fat burning and promote healthy glucose metabolism
  • Lutein: Important for vision health: Lutein, found in your macular pigment, helps protect your central vision, and aids in blue light absorption
  • Zeaxanthin: Important for vision health: Zeaxanthin is found in high concentrations in your macula lutea, the small central part of your retina responsible for detailed central vision
  • Violaxanthin
  • Neoxanthin

Best Vitamin A Foods

Vitamin A is available from a variety of food sources. The recommended daily intake varies with age and other circumstances.^[1] Pregnant or lactating women can normally benefit from taking more each day. As always, consult with your doctor about any major dietary changes you are considering. If you would benefit from more vitamin A foods in your diet, there are a number of great options. ^[5]

Health Benefits of Vitamin A

• Vitamin in A is critical for good vision
• Plays an important role in healthy bone growth ^[7]
• Vitamin A is essential for reproduction ^[6]
• Plays a role in cell division and cell growth ^[7]
• Supports the immune system ^[3]
• Supports skin health ^[8]

Vitamin A is very important for good vision. Lutein and zeaxanthin are particularly crucial for preventing age-related macular degeneration, the most common cause of blindness among seniors. Vitamin A affects vision primarily by regulating gene expression, but in order for this to occur, it must be activated in a two-step process, converting from retinol to retinal, and finally to retinoic acid. As previously explained by Christopher Masterjohn in his article on fat-soluble vitamins:

“Vitamin A supports vision, however, in its semi-activated form as retinal. Retinal binds to a protein known as opsin, forming a vitamin-protein complex known as rhodopsin. Each photon of light that enters our eye and collides with rhodopsin causes the retinal to change shape and release itself from the complex. This event then translates into an electrical impulse that our optic nerve transmits to our brain.

he brain synthesizes myriad such electrical impulses at every moment and interprets them as vision. While the function of opsin is to help generate visual images by binding and releasing vitamin A, opsin can only maintain its proper shape and function when it is bound to zinc. In addition, zinc supports the conversion of retinol to retinal, the form of vitamin A that binds to opsin.

We could predict, then, that vitamin A would only be able to support vision in the presence of adequate zinc. This can be studied by determining dark adaptation thresholds, which determine the dimmest spots of light we are able to see after having spent a period of time in the dark to maximize our visual sensitivity. When vitamin A is insufficient, we lose the ability to see the dimmer spots of light.”

Researchers at Tufts University showed the importance of zinc in a 2000 study,^(source) which included 10 vitamin A deficient patients who had failed the dark-adaptation test. After supplementing with 10,000 IUs of vitamin A for two to four weeks, eight of them achieved normal dark-adaptation thresholds. Two of them, however, also had deficient blood levels of zinc. Vitamin A supplementation alone did not work for them, but when 220 milligrams of zinc per day was added to their regimen for two weeks, their vision was also brought back to normal. These results show that vitamin A requires zinc to support healthy vision.

In addition to zinc, vitamin A also works synergistically with vitamins D and K2, magnesium, and dietary fat. Vitamins A, D, and K2 interact synergistically to support immune health, provide for adequate growth, support strong bones and teeth, and protect soft tissues from calcification. Magnesium is required for the production of all proteins, including those that interact with vitamins A and D. Many of the proteins involved in vitamin A metabolism and the receptors for both vitamins A and D only function correctly in the presence of zinc.

Vitamins A and D also cooperate together to regulate the production of certain vitamin K-dependent proteins. Once vitamin K activates these proteins, they help mineralize bones and teeth, protect arteries and other soft tissues from abnormal calcification, and protect against cell death.

This kind of complexity is one of the key reasons why I strongly recommend getting most of your nutrients from real, whole food (and in when it comes to vitamin D, from sensible sun exposure). This is particularly true for vitamin A, as this will circumvent any toxicity issues. Consuming a well-rounded, nutrient-dense diet, with plenty of vegetables and healthy fats, will go a long way toward warding off nutritional deficiencies and serious nutrient imbalances. Any time you opt to supplement with any given vitamin or mineral, you run the risk of throwing it out of balance with its synergistic partners.

Dangers of Vitamin A Deficiency

Deficiencies may affect the elderly and chronically ill most of all. One of the first signs of vitamin A deficiency is night blindness, as well as scaly skin, brittle hair and nails, poor growth, and poor immunity. ^[9] Those with vitamin A deficiency also tend to have low iron levels, which can lead to anemia. ^[10]

While vitamin A deficiency tends to be minimal in the US, it is quite common in developing countries. One of the earliest signs of vitamin A deficiency is night blindness, which can lead to permanent blindness if left unaddressed. Vitamin A deficiency also lowers your immune function, thereby raising your risk of complications from infectious diseases. It also contributes to:

• Hormonal imbalances
• Infertility
• Mood disorders
• Skin problems such as eczema and acne
• Thyroid dysfunction

Strict vegans who avoid all animal-based foods and alcoholics are two groups that tend to be more prone to vitamin A deficiency than the general population. According to Dr. Andrew Weil:^(source)

“Alcoholics… should consequently include rich food sources of vitamin A in their diets (while concurrently sharply curtailing or eliminating alcohol consumption). Supplements may not be wise for alcoholics, however, because vitamin A is stored in the liver, and existing liver damage could make them more susceptible to vitamin A toxicity. In such cases, a doctor’s supervision is critical.”

Considerations About Vitamin A Intake

Getting too much vitamin A is also a concern. It’s a fat-soluble vitamin, meaning it’s stored in fat cells—typically the liver—where it will be used as needed. Too much vitamin A from supplements in a short or over a long period of time can be toxic and cause a condition known as hypervitaminosis A. Symptoms may include dizziness, nausea, headaches, skin irritation, pain in joints and bones, and even liver damage. ^[5] If you are taking vitamin A supplements, make sure they are from food-based sources like beta-carotene and use as directed.

What About Vitamin A Supplements?

Making the right dietary choices and taking a high-quality supplement can do wonders for your health. Vitamin A has been used for years to encourage bright, vibrant looking skin and Parfait Visage harnesses that benefit to help you care for your skin. ^[8]

When it comes to vitamin A, supplementation carries risks for most people, not just alcoholics, so your best bet is to make sure you’re getting your vitamin A from real food — both animal- and plant-based. Some of the most vitamin A-rich foods include the following:

A number of studies have raised warnings about vitamin A supplementation; showing high doses may lead to toxicity, and may raise your risk of heart disease, cancer, and all-cause mortality. Be particularly cautious with retinol or retinoic acid supplements, as the risk of toxicity is higher with these fat-soluble forms. Synthetic versions should also be strictly avoided. Signs of vitamin A toxicity include:

• Hair loss
• Confusion
• Bone loss
• Liver damage

Plant-derived vitamin A precursors such as beta-carotene, or supplements containing “mixed carotenoids” are far better and carry a much lower risk of toxicity, as your body will not convert more than it needs. Of the carotenoids, beta-carotene is the most efficient converter. Compared to alpha-carotene or beta-cryptoxanthin, half as much beta-carotene is required to convert into the same amount of retinol. If you need to supplement, another option is to take desiccated liver pills.

References:

1. National Institutes of Health. Vitamin A: Fact Sheet for Health Professionals.
2. Hughes, D. A. Effects of carotenoids on human immune function.”> The Proceedings of the Nutrition Society. 58 (3).
3. Chew, B. P. & Park, J. S. Carotenoid Action on the Immune Response.The Journal of Nutrition. 134 (1).
4. Tang, G. Bioconversion of dietary provitamin A carotenoids to vitamin A in humans. American Journal of Clinical Nutrition. 91 (5).
5. National Institutes of Health. Vitamin A: Fact Sheet for Health Professionals.
6. Margaret Clagett-Dame and Danielle Knutson. Vitamin A in Reproduction and Development. doi: 10.3390/nu3040385
7. National Institutes of Health. Vitamin A and Bone Health.
8. Oregon State University. Vitamin A Skin Health.
9. Dowling, J. E. & Wald, G. VITAMIN A DEFICIENCY AND NIGHT BLINDNESS. Proceedings of the National Academy of Sciences of the United States of America. 44 (7).
10. Ning, Y. J. et al. Iron Deficiency and Marginal Vitamin A Deficiency Affect Growth, Hematological Indices and the Regulation of Iron Metabolism Genes in Rats. Journal of Nutrition. 132 (12).

Sources:

• https://www.globalhealingcenter.com/natural-health/health-benefits-of-vitamin-a/
• https://articles.mercola.com/sites/articles/archive/2015/11/16/vitamin-a-types.aspx
• https://www.justlivewell.com/whole-food-vitamins-ascorbic-acid-is-not-vitamin-c/