You probably already knew carrots, squash and leafy greens are nutritious. But did you know why they’re so good for you?

The yellow and orange hues signal the presence of vitamin A. Leafy greens and green superfoods like chlorella also have lots of vitamin A. But the green pigment, chlorophyll, masks it.

Vitamin A, a fat-soluble nutrient, is essential for life.

• Billions of years ago, vitamin A was used to form special light-sensing proteins that helped early organisms orient themselves to the sun and make the most of its energy.[1]

• In the plant world, vitamin A has a long history of working side-by-side with the green pigment chlorophyll to harvest of light energy from the sun.[2]

Vitamin A plays a fundamental role in how life on this planet maximizes its use of sunlight.

And it also plays a huge role in your health. Starting with . . .

Vitamin A Is Essential For Good Vision

As we’ve evolved from bacteria to human, we’ve held onto the power of light-sensing vitamin A rich proteins, called “opsins”.[3]

If you don’t get enough vitamin A in your diet, you won’t be able to make these proteins essential for vision. Consequently, vitamin A deficiency can lead to vision problems. In fact, worldwide vitamin A deficiency is one of the leading causes of blindness.[4]

But vitamin A’s role in the body has evolved to impact more than just vision health . . .

Vital For Immune System Strength

Without vitamin A, your immune system won’t do much good.

Even kids who are mildly vitamin A deficient end up with a much higher risk of respiratory diseases and diarrhea.[5]
Firstly, vitamin A seems to help our white blood cells differentiate. Instead of being just another cop on patrol, these cells gain the rank of detective thanks in part to vitamin A. Consequently, you can have a more sophisticated internal defense force.[6]

Secondly, your body produces a special molecule with vitamin A that tells these same white blood cells and other immune cells to get active.[7]

But there’s a third way vitamin A helps strengthen your immunity that many of us often overlook . . .

Keep Your Skin Healthy With Vitamin A

In an earlier article on natural skin care, holistic dermatologist Dr. Andrew Racette noted that vitamin A is one of his favorite nutrients for skin health. He pointed out that this skin-loving vitamin seems to play a role in the production of collagen and your skin’s ability to hold onto water.

These skin-nourishing qualities explain why vitamin A seems to reduce wrinkles so well![8]

But it’s not just a vanity vitamin when it comes to skin . . .

Some nutritionists call vitamin A the “anti-infective nutrient”[9] because it plays such a key role in keeping your body’s first defensive barrier – your skin and mucus membranes – strong and healthy.

• In one set of early surgical studies from the 1960’s on this nutrient, researchers showed vitamin A sped up wound-healing dramatically.[10]

• Other studies indicate vitamin A protects your skin from UV damage. [11,12]

Clearly vitamin A does some great things in your body. But there’s one particular reason you want to get this nutrient from vitamin A-rich whole foods like chlorella or pumpkin, not supplements . . .

Warning: The Secret To Safe Vitamin A Nutrition

Along with all this good stuff about vitamin A, there’s a catch . . .

Vitamin A can also be toxic. Too much vitamin A has been linked to increased risk for lung cancer and birth defects, for example.

But before you get nervous, consider this simple solution:
See, most whole food sources don’t contain vitamin A, but beta-carotene. Beta-carotene is also called pre-vitamin A. Your body converts beta-carotene into vitamin A.

Beta-carotene from whole food sources are safe. Your body carefully limits the amount of Vitamin A you get by regulating the amount of beta-carotene it converts into vitamin A.[13]

If you eat more beta-carotene than your body can use, your body simply gets rid of the extra. In contrast, the vitamin A found in supplements gets stored in your fat where it can build up to unhealthy levels.

One of my favorite whole food sources of pre-vitamin A nutrition is the green alga, chlorella. Ounce per ounce, chlorella is a vitamin A powerhouse, giving you six times the vitamin A as spinach. It’s one of the best sources of this nutrient. Chlorella’s vitamin A is all in the safe, beta-carotene form.

So now you know why vitamin A is so essential. And you also know the secret to safe vitamin A nutrition . . . With pre-vitamin A-rich foods – not supplements – you can safely feed your eyes, immune system and skin. For sharper vision, strong immunity, and healthy skin, nothing beats the power of vitamin A.


[1] Ming Zhong et al. Retina, Retinol, Retinal and the Natural History of Vitamin A as a Light Sensor
Nutrients. 2012 December; 4(12): 2069–2096.
[2] Anonymous. What is photosynthesis. South Carolina Department of Natural Resources website.
[3] Ming Zhong et al
[4] Vitamin A. Linus Pauling Micronutrient Information Center website.
[5] Semba RD. Impact of vitamin A on immunity and infection in developing countries. In: Bendich A, Decklebaum RJ, eds. Preventive Nutrition: The Comprehensive Guide for Health Professionals. 2nd ed. Totowa: Humana Press Inc; 2001:329-346.
[6] Cassani B et al, Vitamin A and immune regulation: Role of retinoic acid in gut-associated dendritic cell education, immune protection and tolerance. Mol Aspects Med. 2012 February; 33(1): 63–76.
[7] Semba RD. The role of vitamin A and related retinoids in immune function. Nutr Rev. 1998;56(1 Pt 2):S38-48.
[8] JAMA and Archives Journals (2007, May 22). Vitamin A Helps Reduce Wrinkles Associated With Natural Skin Aging. ScienceDaily website.
[9] Semba RD. Impact of vitamin A on immunity and infection in developing countries. In: Bendich A, Decklebaum RJ, eds. Preventive Nutrition: The Comprehensive Guide for Health Professionals. 2nd ed. Totowa: Humana Press Inc; 2001:329-346.
[10]Hunt T et al. The effect of vitamin A in reversing the inhibitory effects of cortisone on open wound healing in animals and man. Annals of Surgery, 1969.
[11] Stahl W et al. Bioactivity and protective effects of natural carotenoids. Biochim Biophys Acta. 2005 May 30;1740(2):101-7. Epub 2004 Dec 28.
[12] Krinsky NI et al. Carotenoid actions and their relation to health and disease. Mol Aspects Med. 2005 Dec;26(6):459-516. Epub 2005 Nov 23.
[13]Dietary Supplement Fact Sheet: Vitamin A and Carotenoids. Office of Dietary Supplements, National Institutes of Health.

Author's Bio: 

About Dr. Michael E Rosenbaum, MD
Dr. Michael E. Rosenbaum is a 35-year veteran and widely recognized pioneer in the field of nutritional medicine, alternative healthcare and medical acupuncture. As one of America's most respected experts in natural health and healing, Dr. Rosenbaum has been a frequent lecturer to professional medical groups and has participated in numerous television and radio talk shows. He is also an esteemed member of the Sun Chlorella Advisory Board, which helps guide the medical innovation behind Sun Chlorella products.

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