All about fruitarianism with a long-term fruitarian, Lena

Retinoids retinol, retinal, and retinoic acid - 3 active forms of vitamin A - "preformed" vitamin A.

Beta carotene can easily be converted to vitamin A by the human body. 

Large amounts of supplemental vitamin A (but not beta carotene) can be harmful to bones.

Vitamin A keeps tissues and skin healthy, plays an important role in bone growth. Diets rich in the carotenoids alpha carotene and lycopene seem to lower lung cancer risk. Carotenoids act as antioxidants. Foods rich in the carotenoids lutein and zeaxanthin may protect against cataracts. Essential for vision lycopene may lower prostate cancer risk.

Recommended daily amount: 700 mcg - 900 mcg or 3 mg - 6 mg beta-carotene (~ 1 cup of raw cantaloupe or sweet red peppers, or 2 mangoes, or 1/5 of one baked sweet potato). 

Because the body converts all dietary sources of vitamin A into retinol, 1 mcg of physiologically available retinol is equivalent to the following amounts from dietary sources: 1 mcg of retinol, 12 mcg of beta-carotene, and 24 mcg of alpha-carotene or beta-cryptoxanthin. From dietary supplements, the body converts 2 mcg of beta-carotene to 1 mcg of retinol.

Marcel Proust

The real voyage of discovery lies not in seeking new landscapes, but in having new eyes. 

Carotenoids

Carotenoids are a class of more than 750 pigments synthesized by plants, algae, and photosynthetic bacteria. These richly colored molecules are the sources of the yellow, orange, and red colors of many plants. Fruit and vegetables provide most of the 40 to 50 carotenoid phytonutrients found in the human diet.

The most common carotenoids in North American diets are α-carotene, β-carotene, β-cryptoxanthin, lutein, zeaxanthin, and lycopene. 

Provitamin A carotenoids - α-carotene, β-carotene, and β-cryptoxanthin - can be converted by the body to retinol (vitamin A), but not lutein, zeaxanthin, and lycopene. 

Dietary lutein and zeaxanthin help maintain optimal visual function - they absorb damaging blue light that enters the eye.

The results of observational studies suggest that diets high in carotenoid-rich fruit and vegetables are associated with reduced risks of cardiovascular disease and some cancers. But high-dose β-carotene supplements did not

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