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Daily handful of hazelnuts increases elderly gentlemen's testosterone levels
As men get older, their testosterone levels drop. A Turkish animal study suggests that supplementation with hazelnuts may prevent this decline.
Young and old rats in control groups were fed standard food without additives.
Hazelnuts are a good dietary source of vitamin E. A handful of hazelnuts provide more than seventy percent of all the vitamin E you need each day. For this reason, the researchers gave a control group of older rats standard food plus extra vitamin E. This way they could see whether vitamin E could explain any health effects of hazelnuts. If these rats had been adult humans, they would have received half a gram of vitamin E in the form of alpha-tocopherol acetate daily.
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Vitamin E had the same effect on testosterone levels as hazelnuts. You should also bear in mind that the dose used is very high. Nutritionists have set the maximum safe daily intake of the vitamin E at 300 milligrams. A handful of hazelnuts a day is safer.
In addition to vitamin E, hazelnuts also contain monounsaturated fatty acids and phenolic phytochemicals. [Eur J Clin Nutr. 2010 Nov;64 Suppl 3:S112-20.] It's probably that combination of nutrients in hazelnuts that boosts testosterone levels.
Vitamin E did not increase the viability of the sperm cells of the old rats, hazelnuts did.
"Hazelnut is a nutrient dense food and is rich inmonounsaturated fatty acids, vitamin E, lipid-soluble bioactives, polyphenols, other macro- and micronutrients. High energy content and these healthy components in hazelnut may be responsible for positive and favourable effects on the reproductive system."
"Human intervention trials are needed to corroborate these data."