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Nuts to your health

Published:Wednesday | April 11, 2012 | 12:00 AM

Charlyn Fargo • Contributor

A daily handful of nuts might help some people feel better and may possibly boost heart health, according to the Journal of Proteome Research. Spanish researchers report that just one ounce of mixed nuts increased levels of serotonin, a neurotransmitter linked to mood, energy balance, metabolism and glucose levels. These changes could be especially important to patients with metabolic syndrome.

Researcher Cristina Andres-Lacueva with the University of Barcelona compared serotonin markers in the urine of 42 metabolic syndrome patients over 12 weeks. One group was given a daily dose of mixed nuts (walnuts, almonds and hazelnuts), while the control group was told to avoid nuts. The nut-eating group also showed increased metabolism and higher levels of heart-healthy fats.

Jeffrey Blumberg with Tufts University, which also reported on the study in its February Heath and Nutrition Letter, explains that identifying serotonin is new and surprising. Overall, 20 apparent biomarkers of nut intake (from among hundreds of compounds measured) were found, including 19 others previously linked to nut consumption.

Eating one ounce of nuts - about a quarter cup - a day is more than most Americans consume on a daily basis, says Blumberg. While this is a small study, other studies have shown that nuts have health benefits because of their 'good' fats. A note of caution, however: nuts are high in calories. If you boost nut consumption, you have to substitute them for something else so total calories don't increase. An ounce of walnuts has 185 calories.

Confused about Vitamin D

Q: I'm totally confused by the conflicting things I'm hearing about whether vitamin D can reduce cancer risk. What's the current advice about vitamin D?

A: The current national recommendations for vitamin D from the Institute of Medicine (IOM) are 600 International units per day for adults up to age 70 and 800 IU/day for older adults, but these are based primarily on evidence for bone health.

The IOM report concluded that research on whether vitamin D reduces cancer risk is inconsistent. In cell studies, researchers have identified ways that vitamin D can keep cancer in check, and in other studies they have shown that animals deficient in vitamin D show early signs of prostate cancer and develop faster-growing colon cancer. Some large human studies do link lower blood levels of vitamin D with greater risk of certain cancers, but overall, these studies show mixed results.

In fact, there are also studies that link very high blood levels of vitamin D (achievable only with supplements) with greater risk of pancreatic and prostate cancer. A new analysis involving more than 2400 women followed for 10 years shows no link between blood levels of vitamin D and cancer-related or overall deaths.

"Before we assume there's any cancer protection from higher amounts, we need rigorous controlled testing," said Dr JoAnn Manson, a professor at Harvard Medical School. She's directing the Vitamin D and OmegA-3 Trial, the first large-scale randomised trial of vitamin D (2,000 IU daily) in the prevention of cancer and cardiovascular disease (, and other trials are under way as well.

Charlyn Fargo is a registered dietitian at Creators Syndicate writers and cartoonists, the Creators Syndicate website at