People with high levels of alpha-carotene in their blood, that is, those who eat lots of fruit and vegetables, have a smaller risk of dying early and are more likely to live longer than others, researchers from the CDC (Centers for Disease Control and Prevention), Atlanta, Georgia wrote in the journal Archives of Internal Medicine. Alpha-carotene, beta-carotene and lycopene are carotenoids and are found in plants and microorganisms. They can counteract the oxygen-related damage to DNA, fats and proteins which contribute to the development of cancer, heart disease and other chronic illnesses.
Humans get carotenoids either from some fruit and vegetables, antioxidant supplements, or both. An example of an alpha-carotene rich fruit is cantaloupe melon.
The following vegetables are rich in alpha-carotene:
- Yellow-orange vegetables
– Sweet potatoes
– Winter squash
- Dark-green vegetables
– Green beans
– Green peas
– Turnips greens
– Leaf lettuce
The authors explain that consuming plenty of fruit and vegetables is linked to less risk of developing chronic diseases. However, no randomized controlled trials have ever linked this to beta-carotene supplements.
- “Therefore, carotenoids other than beta-carotene may contribute to the reduction in disease risk, and their effects on risk of disease merit investigation.”
Chaoyang Li, M.D., Ph.D., and team examined the relationship between risk of death and alpha-carotene consumption in 15,318 men and women aged 20 or more – they had all taken part in the Third National Health and Nutrition Examination Survey Follow-up Study. Between 1988 and 1994 they provided blood samples and had medical examinations, and were then followed up at the end of 2006 to find out what the causes of death of those who had died were.
The researchers found that:
- 3,810 study participants died
- Those with 2 to 3 micrograms per deciliter of alpha-carotene in their blood had a 23% lower risk of dying compared with those whose levels were between 0 and 1 micrograms per deciliter
- Those with 4 to 5 micrograms per deciliter of alpha-carotene in their blood had a 27% lower risk of dying compared with those whose levels were between 0 and 1 micrograms per deciliter
- Those with 6 to 8 micrograms per deciliter of alpha-carotene in their blood had a 34% lower risk of dying compared with those whose levels were between 0 and 1 micrograms per deciliter
- Those with 9 micrograms per deciliter of alpha-carotene in their blood had a 39% lower risk of dying compared with those whose levels were between 0 and 1 micrograms per deciliter
They were able to isolate certain illnesses and deaths from other causes and link them to alpha-carotene concentrations. Those with higher concentrations of alpha-carotene in their blood had a lower risk of dying from cardiovascular disease or cancer individually, as well as from all other causes.
The authors wrote:
- “The association between serum alpha-carotene concentrations and risk of death from all causes was significant in most subgroups stratified by demographic characteristics, lifestyle habits and health risk factors.”
Although alpha-carotene and beta-carotene are chemically very similar, alpha-carotene appears to be better at undermining the growth of cancer cells in the skin, liver and brain, the researchers said.
- “Moreover, results from a population-based case-control study of the association between the consumption of fruits and vegetables and risk of lung cancer suggest that consumption of yellow-orange (carrots, sweet potatoes or pumpkin and winter squash) and dark-green (broccoli, green beans, green peas, spinach, turnips greens, collards and leaf lettuce) vegetables, which have a high alpha-carotene content, was more strongly associated with a decreased risk of lung cancer than was consumption of all other types of vegetables.”
A good way to avoid dying early is to increase fruit and vegetable consumption, the authors concluded. They added that further research is needed to look into the health benefits of alpha-carotene.
Chaoyang Li, MD, PhD; Earl S. Ford, MD, MPH; Guixiang Zhao, MD, PhD; Lina S. Balluz, MPH, ScD; Wayne H. Giles, MD, MS; Simin Liu, MD, ScD
Arch Intern Med. Published online November 22, 2010. doi:10.1001/archinternmed.2010.440
Written by Christian Nordqvist