vitamin A

Functions
  • Vision; immune function
  • Bone development; growth; reproduction; detoxification
  • Health and structure of skin and mucuous membranes / epithelial tissue
  • Adrenal and thyroid hormone manufacture and activity;
  • Structure and function of nerve cells
Sources notes 2 types

  • Beta-carotenes and other carotenes from fruit and vegetables, source of provitamin A and converted in body to vitamin A is
  • Aldehydes, preformed vitamin A in retinal form primarily found in animal tissue
  • Best source: green leafy and yellow-orange  vegetables
Vegetable Sources Red chilli; Dandelion greens; Carrots; Collard greens; Kale; Sweet potato; Parsley; Spinach; Turnip greens; Swiss chard; Beet greens; Chives; Butternut squash; Watercress; Red Bell Peppers; Squashes (Hubbard, pumpkin, acorn)
Fruit Sources Dried Apricots, Mangoes, Cantaloupe melon, Papayas, Nectarines, Prunes, Peaches, Sour cherries
Nut and seed sources
Absorption and function notes
  • Fat soluble
  • Combine with fat (highly dependent on fat for absorption)
Deficiency factors
  • Poor night vision and dry eyes; poor wound healing; hard, dry, dysfunctional tissue where cellular turnover is great – eye, skin, organs (e.g. lungs)
  • Recurrent infections / infection susceptibility: used up more during infections and detoxification
  • Fatigue; poor fat absorption and metabolism; weight loss
  • Steroid hormone dysfunctions; poor smooth and bone function
Toxicity
  • Toxic in large sustained doses over time, but no toxicity with beta-carotene; liver disease patients susceptible to toxicity
  • Oral contraceptives and Lipitor raise vitamin A blood levels
  • Symptoms of toxicity – weight loss, appetite loss, dry shedding skin, hair loss, fatigue and irritability, bone and joint pain, headache and intracranial pressure

Adapted from:

Murray, M. (2005). Encyclopedia of Healing Food. New York, N.Y.: Atria Books

Bland, J., Costarella, L., Levin, B., Liska, D., Lukaczer, D., Schlitz, B., Schmidt, M., Lerman, R., Quinn, S., Jones, D. (2004). Clinical Nutrition: A Functional Approach, Second Edition. Gig Harbor, WA: The Institute for Functional Medicine

Resources

National Institute of Health fact sheet on Vitamin A including details on the RDA from various sources

Linus Pauling Institute in depth scientific information about Vitamin A

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