Vitamin A is a very important fat-soluble vitamin. This article teaches you the role of Vitamin A, and the deficiency and toxicity symptoms. Learn what foods to eat to obtain the correct amount of this important vitamin. After all- food is medicine! So let your food work for you and keep you well, heal your infections… and possibly get rid of a few of those wrinkles too!
Roles of Vitamin A in the body
- Necessary for maintaining the health of the respiratory system
- Needed for healing skin
- Boosts/ strengthens the immune system
- Heals inflamed mucus membranes
- Promotes vision
- The body cannot use protein without vitamin A.
- Support growth and reproduction (needed for sperm development, normal foetal development and childhood growth).
- A powerful antioxidant
- Needed for protein synthesis and cell differentiation- (see further down for further explanation).
- Lastly, Vitamin A slows the aging process. It is a well-known wrinkle eliminator!
Vitamin A is an antioxidant
It helps protect against developing cancer, heart disease, stroke, and other diseases. It also lowers cholesterol levels. People receiving radiotherapy for cancers have greatly benefited from taking Vitamin A in high doses to heal ulcers caused by the radiation.
Protein synthesis and cell differentiation
Protein synthesis and cell differentiation enables the maintenance of the health of all epithelial tissues including the skin. Goblet cells are also differentiated, and these glands synthesis and secrete mucous. Mucous protects epithelial cells from microorganisms invading! It stops you getting sick! It stops infections of the kidneys, bladder, lungs, gastrointestinal system, vagina, inner ear and mucous membranes.
Vitamin A Deficiency
Night blindness is the first detectable sign of vitamin A deficiency. A slow recovery of vision after seeing a flash of bright light is common in deficiency. Total blindness also occurs. Eye inflammation is common.
A deficiency of Vitamin A also leads to an increase in susceptibility of infections of the respiratory tract, GI tract, urinary tract, the vagina and also the inner ear.
Sadly, measles kills approximately 2 million children each year in developing countries. Interestingly, the severity of the illness correlates with the amount of vitamin A deficiency the child has. Deaths from measles is often due to related infections. Providing these children large doses of Vitamin A reduces their risk of dying from related infections. Giving Vitamin A also protects again malaria, lung disease, and HIV to name a few.
Skin and hair symptoms
Another common symptom of Vitamin A deficiency is rough, dry, prematurely aged and wrinkled skin, skin diseases in general, dry hair, dandruff all occur.
Dryness of mucous membranes
It also causes a decrease in mucous production via goblet cells (discussed earlier). This occurs in the mouth, respiratory, reproductive, and gastrointestinal systems. The latter causes impaired digestion, which leads to less nutrient absorption. And this can lead to other deficiencies.
Lastly, other symptoms such as a loss of sense of smell and allergies can occur.
Conversely, toxicity is much less common than deficiency. It is unlikely to occur if your only source of Vitamin A is from your diet. However, taking supplements can cause toxicity if care is not taken.
Excessive amounts can cause:
- Weak bones, contributing to osteoporosis
- Joint pain
- Teratogenic risk (birth defects)
- Abdominal pain
- Enlarged liver and/or spleen; elevated liver enzymes
- Gastrointestinal disturbances
- Hair loss
- Nausea and vomiting
Food sources of Vitamin A
Beta Carotene is found in plants and is the precursor to Vitamin A. Retinoids are derived from animal products and are then converted into Vitamin A in the gut. Beta carotene absorption and conversion into Vitamin A is significantly less efficient than the retinoids from animal products.
Richest sources are from animal products:
- Beef or lamb liver
- Oily fish
- Fish liver oils
- Full fat milk, cheese, butter. It is lost in skim milk.
Liver- liver is a rich source because Vitamin A is stored there in animals and people alike. However, toxins are also stored in the liver, so it is wise to only consume it rarely, and always from organic sources.
- Dark leafy greens: spinach, spirulina, kale, parsley, turnip greens, beet greens, dandelion greens
- Deep orange veggies: carrots, sweet potatoes, pumpkin.
- Asparagus and broccoli
Adults need between 4,000-5,000iu daily. People with chronic or acute diseases need more, as do those who are pregnant or lactating. Though, as mentioned, it is VERY important not to take too much whilst pregnant as birth defects can result. More is also required in winter, and if the person reads or does focussed work excessively.
A heaped tablespoon of spirulina provides 25,000iu of Vitamin A. An 100g serve of kale provides 8,300iu. A 100g portion of carrots provides 28,000iu. You can get this from your diet people!! However, in samples tested from different growing locations, some carrots provided as little as 100iu. Organic carrots will provide many more nutrients, and much less toxins, across the board, not just for Vitamin A.
In some people, such as people with diabetes or hypothyroidism, beta carotenes do not covert well into vitamin A in the body. These people require their sources (retinol) from animal products, not plants.
Lastly, Vitamin A and Zinc have a strong synergistic relationship. They both enhance each others effect greatly when together. Both nutrients are required for immune system functioning, skin function, mucous membranes, bones, growth and development, and vision to name a few overlaps. Both Zinc and Vitamin A can lower the sodium levels on a Hair Tissue Minerals Analysis– the reflection of the mineral and heavy metal levels in the body tissues (as opposed to the serum blood).
This very important vitamin is easily obtained in your diet. You’ve learnt more strong reasons for you to eat LOTS of vegetables of different colours, and enjoy full fat dairy in your diet. ‘
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Rolfes et al (2006) Understanding normal and clinical nutrition. 7th Edition. USA
Pitchford, Paul (1993) Healing with whole foods: oriental traditions and modern nutrition. USA