Men's Osteoporosis Support Group
Diet pattern and bone mineral density; lycopene and serum testosterone
J Nutr. 2011 Jun 8. [Epub ahead of print]. An Energy-Dense, Nutrient-Poor Dietary Pattern Is Inversely Associated with Bone Health in Women. McNaughton SA and others. PMID: 21653576. This study evaluated the dietary patterns of 527 Australian women aged from 18-65 years and evaluated five different patterns in relation to the women's bone mineral density (BMD). They found two of the dietary patterns were significantly related to BMD.
The energy-dense, nutrient-poor pattern was inversely associated with BMD, that is, that group had lower BMD than the nutrient-dense pattern. The first pattern included, “ . . . high consumption of refined cereals, soft drinks, fried potatoes, sausages and processed meat, vegetable oils, beer, and takeaway foods and low consumption of other vegetables, vegetable dishes, tea, coffee, fruit, wholegrain breads, and breakfast cereals.” The second pattern included, “. . . high consumption of legumes, seafood, seeds, nuts, wine, rice and rice dishes, other vegetables, and vegetable dishes and low consumption of bacon and ham.”
The authors concluded, “This study identified specific dietary patterns associated with BMD and total body BMC among women and provides evidence that will contribute to potential food-based strategies for improving bone health.”
Editor's comments. Although this study involved only women, there is no reason to believe that men wouldn't have had similar results. Logically, diet patterns should affect men's bone health similar to that of women.
Presumably the improvement in BMD with the nutrient-dense pattern would be because that diet supplied nutrients essential to healthy bone formation and maintenance while the energy-dense diet mainly provided calories, but inadequate nutrition.
One of the important nutrients for bone health is lycopene, an antioxidant found in tomatoes and other red fruits and vegetables. See this Update for a discussion of the negative effects of lycopene depletion on BMD. Note that lycopene, and other nutrients often combined with it in food sources, have many other health benefits. See this website for a thorough discussion of that topic.
Possible negative effect of tomato products on men's serum testosterone
With every good thing there is also often a precautionary note that too much of it might not be so good. A 2006 study by Campbell JK and others, PMID: 17056806, found rats fed high levels of tomato-derived products had reduced serum testosterone. This article is also available as free full text. The authors found that the reduction in testosterone was approximately 40-50% during a four-day study of the tomato-derived foods diet. Presumably this could be enough reduction for men to have negative impacts from the reduced serum testosterone levels, i.e., decreased libido and/or decreased BMD.
So we have tomato products that produce multiple benefits to human health if eaten regularly, and a single study using rats that found a potential risk to male rats' health from reduced serum testosterone when eating tomato products. How do we interpret the risks and benefits from eating tomatoes and other foods with lycopene? I wonder why there isn't more in the literature with men who often eat tomatoes reporting to their physicians with the chief complaint of reduced libido? Certainly there are many men who eat lots of tomato products during their lives. I didn't find a single case report in PubMed. And I've seen no follow-up study using human males to test the effects of a high-tomato diet on testosterone and libido, as well as other possible negative effects.
One possible explanation in older males is that, as has been shown in a study by Marberger M and others, PMID: 20955266, there is little correlation between low serum testosterone and sexual dysfunction, such as decreased libido. So maybe men who eat large amounts of tomato products are walking around with reduced serum testosterone levels but have no noticeable ill effects. And the study related decreased libido, and other sexual dysfunctions, to increasing age. So, although we are likely tempted to point to low testosterone as the source of decreased libido, studies show that in older men it is their age that is better correlated.
I have suggested in a recent Osteoporosis Issues article that eating tomatoes, as either sun-dried or tomato paste, as one way to help maintain a low-acid, alkaline-forming diet that might promote improved BMD. Not only are tomato products high in micronutrients, but they are very alkaline forming, having high levels of potassium in particular. For anyone following my suggestion it would be interesting to have your serum testosterone tested to see if you have low levels. I would love to hear from anyone who does this what the results are. And, if I have my serum testosterone tested while eating a diet with moderate to high amounts of tomato products, I'll report the results of the test. Until more research is done, I suggest discussing this with whomever you see for your osteoporosis, especially if you eat a diet high in tomato products.