Wednesday, September 3, 2014
Wisdom Wednesday: CAROTENOIDS
Beta-carotene is the one you all know. The human body can convert some carotenoids to vitamin A. In fact, there are 60 carotenoids that we can convert to vitamin A, beta-carotene is just the most common.
For most populations, carotenoids are the major source of vitamin A in the diet. Animal foods provide a rich source of retinol, which also has vitamin A activity in the body. The Native American Eskimo population derives most of its vitamin A from animal foods as their sources of plant food are somewhat limited.
Most of the carotenoids can not be converted into vitamin A. In fact there are over 600 known carotenoids, so less than 10% are used to make vitamin A.
Carotenoids give plants the colors yellow, red, and orange. They create the fall foliage as the chlorophyll production slows this time of year. Carotenoids facilitate photosynthesis and act as anti-oxidants. The non-provitamin A carotenoids also function as anti-oxidants in the human body. It has been suggested that the carotenoids may account for the protective benefits of diets high in fruits and vegetables against cancer and other chronic diseases.
Lycopene is a very common carotenoid that is abundant in tomatoes. It has become very popular because studies have linked it with cancer prevention, especially prostate cancer. As an “aging male”, I make sure I consume some lycopene rich foods everyday. It’s easy to add a slice of tomato to any meal.
Lutein and zeaxanthin are carotenoids present in high concentrations in the retina of the eye. These pigments appear to provide a protective barrier from the damaging effects of blue-wavelength photons. The yellow color of these carotenoids actually absorbs up to 90% of the harmful rays. This effect is thought to protect against age related macular degeneration. Lutein is now found in virtually all “eye supplements”.
The xanthophylls are a group of carotenoids that also seem to support vision. Studies indicate that cataract patients show demonstrable improvements in both visual acuity and visual field when xanthophylls are supplemented in the diet.
THE BOTTOM LINE:
In 2007 only 500 carotenoids had been discovered. In just a few years, that number is over 600 and climbing. If you have a specific condition that might benefit from one or more of these quasi-vitamins, then add a supplement to your diet. For the rest of us, the key is to eat the food. When you pick your fruits and vegetables, make sure you get lots of color, not just the green stuff. Remember that orange, yellow, and red are the colors of the carotenoids.
Please try to avoid that reductionist thinking that tries to find the one chemical in a food that is responsible for its health benefits. Just the suggestion that carotenoids are the “one thing” in plant food that protects against cancer is a prime example of reductionist thinking; even if that one thing is really over 600 things. There are thousands upon thousands of organic compounds necessary to support healthy life, and they’re all in the food.