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Vitamin A (and the Carotenoids)
DescriptionA fat soluble vitamin.Vitamin A comes in two forms:1/ Carotene (Pro vitamin A) must be converted into vitamin A before it can be absorbed in the body2/ Preformed Vitamin AIn the retina, transformation of light energy into the nerve impulses the brain perceives as visionProper growth and development of the skin and mucus membranesAntibody production by white blood cells and activity of T cellsSteroid hormone synthesis, including production of corticosteroids, androgens, and oestrogensSperm count and motility in malesGrowth and development during childhood and adolescence Iron transport and erythrocyte productionMyelin synthesis in the nervous system Bone growth and repair
Increased Risk of DeficiencyPoor night visionStress, infection, or surgeryFat malabsorptionDry skinNew-borns (particularly premature infants)Diabetes and hypothyroidism (conversion of carotenes to vitamin A is impaired)AcneEar infectionsBladder infectionsHeavy alcohol consumptionCigarette smokingExposure to air pollution, toxic metals (cadmium)Signs and Symptoms of DeficiencyDryness, itching, and redness of the conjunctivaNight blindness – reduced ability to see in the darkPainful joints and bonesDry itchy skin with rashDecalcification and spontaneous fractures of bonesDry, brittle hair and nailsLoss of sense of smell, taste, and appetiteFatigue AnaemiaPoor growthIncreased vulnerability to infectionsIncreased risk of cancer of the throat, lung, bladder, cervix, prostate, oesophagus, stomach, and colonImpaired reproduction and fertilityIncreased risk of kidney stonesMedications: cholesterol-lowering drugs, laxatives, barbiturates
Good Dietary SourcesBeef liver, Halibut oil, Cod liver oil, 1 whole Egg, Cheddar cheese, Spinach, apricots, carrots, prunes, peaches, kiwifruit, mustard greens, broccoli, kale, beet greens, alfalfa, burdock, cayenne, dandelion, endive, garlic, horseradish, kelp, lemon grass, parsley, raspberries, red clover, watercress, yellow dock.
Signs and Symptoms of ToxicityThinning hairSore lips, bruising, nose bleeds,Bone pain and joint swellingNausea, vomiting, and diarrhoeaDry skin and lips, hair lossHeadache and blurred visionEnlargement of the liver and spleenHypothyroidismHypercalcemiaThese would only occur after mega-dosing. Supplementing with vitamin C simultaneously will prevent side effects.
