Aging causes an increase in oxidative stress and inflammation in our bodies. Along with declining estrogen levels, these changes may lead to bone loss in postmenopausal women. The effects of estrogen on bone have been investigated in great detail, but not much is known about the effects of antioxidants and anti-inflammatory substances on bone. Since vitamin E has both antioxidant and anti-inflammatory properties, it may be beneficial to bones. In order to assess whether vitamin E can affect bone loss, our group studied the relationship between vitamin E and bone turnover markers in postmenopausal women. Bone turnover markers are chemicals in the body that can provide information about bone formation and bone resorption (bone loss) and are measured by either a blood test or urine test. Bone turnover markers can be used in research studies to test the short term effects of diet on bone health. The bone turnover markers that we looked at were : 1) bone alkaline phosphatase (BAP) which is a bone formation marker in the blood and, 2) urinary N-telopeptides/creatinine (uNTx/Cr) which is a bone resorption maker in the urine.
In our study, we looked at relationships between blood levels of two forms of vitamin E and bone turnover markers in a sample of healthy postmenopausal women in the US who participated in a national survey in years 1999-2002. These two forms of vitamin E were alpha-tocopherol and gamma-tocopherol, and are described below in more detail:
Alpha-tocopherol: Has a high antioxidant activity and is the most common form in dietary supplements.
Unfortified food sources: sunflower seeds, almonds, hazelnuts, peanuts; sunflower, safflower and grapeseed oils; avocados; green vegetables
Gamma-tocopherol: Has a high anti-inflammatory property and is the major form of vitamin E in North American diets
Unfortified food sources: Pecans, peanuts; soybean and canola oils
We also looked at the relationship between alpha-tocopherol intake (data was not available for intake of gamma-tocopherol from food sources) from food and supplements and bone turnover markers. It has been shown that high intakes of alpha-tocopherol from dietary supplements can lower blood levels of gamma-tocopherol. We do not know how this change can affect our health. The results of our study were published in June 2012 in the Journal of American Bone and Mineral Research. There were no relationships between alpha-tocopherol intake from food sources and bone turnover markers. As expected, we found that women who used vitamin E supplements had high blood levels of alpha-tocopherol and low blood levels of gamma-tocopherol. These women also had lower levels of BAP (a bone formation marker). We found no relationships between blood levels of alpha-tocopherol and gamma-tocopherol and uNTx/Cr (a bone resorption marker). These results suggest that vitamin E supplements may not help bone health. More research is needed in this area to find out if vitamin E intake from food sources can improve bone health or not.
So what is the bottom line? As long as you have a balanced diet, and do not overeat or completely eliminate one food group, you will not be causing imbalances in your blood levels of various nutrients. Also, unlike supplements, whole and unprocessed foods contain a mixture of different types of vitamin E as well as many other nutrients all of which may play a role in our health. For example almonds are high in vitamin E but they are also high in calcium and magnesium two other important nutrients in bone health. In conclusion, we believe the best way to get nutrients, including vitamin E, is to get them from food sources.
By Maryam S. Hamidi, PhD and Hajera Khaja, M.Sc