Becoming Vegan

Good sources of vitamin C include blackberries, broccoli, Brussels sprouts, cabbage, cantaloupe, citrus fruits, green peas, guava, kiwifruit, leafy greens, mango, papaya, pineapple, raspberries, red peppers (bell and chile), strawberries, sweet potato, tomato, and vegetables in the cabbage family

Carotenoids are present in apricot, broccoli, cantaloupe, carrot, leafy greens, mango, nectarine, papaya, peppers (bell and chile), persimmon, plantain, prunes, pumpkin, sea vegetables, squash, sweet potato, tomato, and turnip.

You can get your recommended daily intake from ½ cup (125 ml) of carrot juice, baked sweet potato, or canned pumpkin, or from ¼ cup (60 ml) of cooked kale. We derive about 470 mcg RAE from ½ cup (125 ml) of cooked spinach or butternut squash or from ½ cantaloupe.

Cooking seems to increase the absorption of some carotenoids, as does including a little fat as part of the meal. Juicing provides even greater carotenoid absorption than cooking. We recommend eating some of these colorful vegetables cooked and others raw.

For centuries, Native Americans had used herbs and cranberries to cure scurvy. And although some early explorers, including Vasco de Gama’s crew in 1499, discovered that citrus fruits could alleviate the condition, it took hundreds of years for European doctors to connect the dots between the disease that had killed thousands and the simple lack of fruits and vegetables. Scientists identified vitamin C in 1912, proved its relationship to scurvy in 1932, and synthesized the vitamin in 1935.

Vitamin C’s role in preventing and curing scurvy is due to its ability to build collagen, an essential component of blood vessel walls, scar tissue, tendons, ligaments, cartilage, and bone. Without vitamin C, the gums and other collagen-containing tissues break down. In addition, vitamin C helps metabolize the amino acid that transports fat to the cells for energy.

Vegan diets, with their abundance of colorful fruits and veggies, can easily provide more than enough vitamin A. Vegan vitamin A intake has been estimated at 1,500 mcg RAE (4,950 IU) for women and 1,200 RAE (3,960 IU) mcg for men per day. The key is to include lots of yellow, orange, red, and green vegetables and fruits. Consuming these with foods that are rich in plant oils, such as olives, avocados, nuts, and seeds, or with oil-based salad dressings, increases carotenoid absorption

There are two forms of vitamin A in food: provitamin A carotenoids from plants, and preformed vitamin A from animal products. The body converts certain carotenoids, such as beta-carotene, to the active form of vitamin A, called retinol. The carotenoids provide many of the beautiful orange, red, and yellow colors in fruits and vegetables. Carotenoids are present in green vegetables too, but the color is masked by the green of chlorophyll. Other carotenoids, such as lycopene, lutein, and zeaxanthin, aren’t converted to vitamin A, but they do have powerful health benefits.

Vitamin A plays an important role in cell differentiation, the process that creates different kinds of cells to carry out specific tasks. In the eye, vitamin A or certain carotenoids help us see at night, prevent cataracts and macular degeneration, and keep the cornea healthy. Vitamin A is required for immune system function and to build and preserve the integrity of the skin and mucous membranes so they can act as protective barriers against bacteria and viruses. Many carotenoids help protect us against cancer and heart disease. Vitamin A is needed for the growth of bones and teeth, for reproduction, and for the production and regulation of hormones.

The liver may be the busiest hub of activity in the body. One of its functions is to detoxify the body, ridding it of substances that are potentially damaging, such as caffeine, medications and other drugs, paint and exhaust fumes, pesticides, and tobacco smoke. The liver recognizes dangerous molecules and transforms them into harmless forms and then facilitates their elimination

and for ages seventy-one and older it’s 20 mcg (800 IU) per day. However, many experts suggest 25 to 50 mcg (1,000 to 2,000 IU) daily for adults. Others advise even higher intakes of up to 100 mcg (4,000 IU), though this is the upper limit a person should take without medical supervision. The tolerable upper limits are lower for younger children. Obese people may have somewhat higher requirements for vitamin D because fat can absorb this vitamin D, making it unavailable to the rest of the body.

The American Academy of Pediatrics recommends a daily intake of 10 mcg (400 IU) of vitamin D starting from the first few days of life. Ask your pediatrician about a suitable intake for your baby, and avoid giving the baby more than the doctor suggests, as too much may cause your child’s bones to harden too soon.

When oxygen joins with certain molecules, oxidation occurs, causing chain reactions of rampaging molecules called free radicals. Free radicals damage cells and DNA, effectively aging our bodies and increasing our risk for diseases including cancer, cardiovascular disease, cataracts, macular degeneration, diseases of the nervous system (such as Alzheimer’s and Parkinson’s), and premature aging of skin. The body also produces free radicals during normal metabolism, but if you smoke, drink alcohol, or are exposed to pollutants or radiation, including too many UV rays from the sun, free radicals can multiply rapidly. This chain reaction can only be stopped by substances that intervene and deactivate the process. These substances are called antioxidants.

If you live north of that latitude, you probably need to take a vitamin D supplement and eat fortified foods in the winter, in addition to spending time outdoors on sunny days in summer