In the News

Latest Analysis Confirms Suboptimal Vitamin D Levels in Millions of US Children

Mediterranean Diet Associated With Reduced Risk of Depression

Incidence of Urogenital Birth Defects 33% Greater in Villages Sprayed With DDT

Trigger of Deadly Food Toxin Discovered

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Latest Analysis Confirms Suboptimal Vitamin D Levels in Millions of US Children

Millions of children in the United States between the ages of 1 and 11 years may suffer from suboptimal levels of vitamin D, according to a large nationally representative study published in the November issue of Pediatrics.

The study, led by Jonathan Mansbach, MD, at Children's Hospital in Boston, is the most up-to-date analysis of vitamin D levels in US children. It builds on the growing evidence that levels have fallen below what's considered healthy and that black and Hispanic children are at particularly high risk.

Both the optimal amount of vitamin D supplementation and the healthy blood level of vitamin D are under heated debate in the medical community. Currently, the American Academy of Pediatrics (AAP) recommends children should have vitamin D levels of at least 50 nmol/L (20 ng/mL). Other studies in adults, however, suggest that vitamin D levels should be at least 75 nmol/L (30 ng/mL), and possibly 100 nmol/L (40 ng/mL), to reduce the risk of heart disease and specific cancers.

Mansbach and colleagues from the University of Colorado-Denver and Massachusetts General Hospital used data from the National Health and Nutrition Examination Survey (NHANES) to look at vitamin D levels in a nationally representative sample of roughly 5000 children from 2001 to 2006. Extrapolated to the entire US population, their analysis suggests that roughly 20% of all children fell below the recommended 50 nmol/L. Moreover, more than two-thirds of all children had levels below 75 nmol/L, including 80% of Hispanic children and 92% of non-Hispanic black children.

Mansbach and his coauthors recommend that all children take vitamin D supplements because of the generally low levels that they found and the potential health benefits of boosting vitamin D to normal levels. Vitamin D improves bone health and prevents rickets in children, and recent studies suggest that it also may prevent a host of common childhood illnesses, including respiratory infections, childhood wheezing, and winter-related eczema.

Although sun exposure generates healthy doses of vitamin D, it can also cause skin cancer. Dermatologists and the AAP recommend that children wear sun block, which blocks the skin's ability to make vitamin D. Furthermore, children with more highly pigmented skin require much more sun exposure than fair-skinned children to obtain healthy levels of vitamin D. Vitamin D can also be obtained from certain foods, like liver and fatty fish, but almost children in the United States generally don't consume these foods in high enough quantities to match the vitamin D that can be provided by summer sunshine or vitamin D supplements.

In the study, children taking multivitamins that included vitamin D had higher levels overall, but this accounted for less than half of all children. Mansbach recommends that all children take vitamin D supplements, especially those living in higher latitudes, where the sun is scarce in the wintertime.

Mediterranean Diet Associated With Reduced Risk of Depression

Individuals who follow the Mediterranean dietary pattern?rich in vegetables, fruits, nuts, whole grains, and fish?appear less likely to develop depression, according to a report in the October issue of Archives of General Psychiatry.

The lifetime prevalence of mental disorders has been found to be lower in Mediterranean than in Northern European countries, according to background information in the article. One plausible explanation is that the diet commonly followed in the region may be protective against depression. Previous research has suggested that the monounsaturated fatty acids in olive oil?used abundantly in the Mediterranean diet?may be associated with a lower risk of severe depressive symptoms.

Almudena Sánchez-Villegas, BPharm, PhD, of University of Las Palmas de Gran Canaria and Clinic of the University of Navarra, Pamplona, Spain, and colleagues studied 10 094 healthy Spanish participants who completed an initial questionnaire between 1999 and 2005. Participants reported their dietary intake on a food frequency questionnaire, and the researchers calculated their adherence to the Mediterranean diet based on 9 components (high ratio of monounsaturated fatty acids to saturated fatty acids; moderate intake of alcohol and dairy products; low intake of meat; and high intake of legumes, fruit and nuts, cereals, vegetables, and fish).

After a median of 4.4 years of follow-up, 480 new cases of depression were identified: 156 in men and 324 in women. Individuals who followed the Mediterranean diet most closely had a greater than 30% reduction in the risk of depression than whose who had the lowest Mediterranean diet scores. The association did not change when the results were adjusted for other markers of a healthy lifestyle, such as marital status and use of seatbelts.

"The specific mechanisms by which a better adherence to the Mediterranean dietary pattern could help to prevent the occurrence of depression are not well known," the authors write. Components of the diet may improve blood vessel function, fight inflammation, reduce risk for heart disease, and repair oxygen-related cell damage, all of which may decrease the chances of developing depression.

"However, the role of the overall dietary pattern may be more important than the effect of single components. It is plausible that the synergistic combination of a sufficient provision of omega-three fatty acids together with other natural unsaturated fatty acids and antioxidants from olive oil and nuts, flavonoids and other phytochemicals from fruit and other plant foods and large amounts of natural folates and other B vitamins in the overall Mediterranean dietary pattern may exert a fair degree of protection against depression," the authors write.

Incidence of Urogenital Birth Defects 33% Greater in Villages Sprayed With DDT

Women who lived in villages sprayed with dichlorodiphenyltrichloroethane (DDT) to reduce malaria gave birth to 33% more baby boys with urogenital birth defects (UGBD) between 2004 and 2006 than women in unsprayed villages, according to research published online by the United Kingdom?based urology journal BJUI.

Women who stayed at home in sprayed villages rather than being at school or working had 41% more baby boys with UGBDs, such as missing testicles or problems with their urethras or penises. The authors suggest that this is because these women spent more time in homes where domestic DDT-based sprays are still commonly used to kill the mosquitoes that cause malaria, even in areas where organized mass spraying no longer takes place.

Researchers led by the University of Pretoria in South Africa studied 3310 boys born to women from the Limpopo Province, where DDT spraying was carried out in high-risk areas between 1995 and 2003 to control malaria. The 2-year study included 2396 boys whose mothers had been exposed to DDT and 914 whose mothers had not.

The study showed that 357 of the boys included in the study—just under 11%—had UGBDs. The incidence of UGBDs was significantly higher if the mother came from a sprayed village.

"If women are exposed to DDT, either through their diet or through the environment they live in, this can cause the chemical to build up in their body," explains lead author Professor Riana Bornman from the university's Department of Urology.

"DDT can cross the placenta and be present in breast milk and studies have shown that the residual concentration in the baby's umbilical cord are very similar to those in maternal blood.

"It has been estimated that if DDT exposure were to cease completely, it would still take 10 to 20 years for an individual who had been exposed to the chemical to be clear of it. Our study was carried out on boys born between 2004 and 2006, 5 to 9 years after official records showed that their mothers had been exposed to spraying.”

A number of other factors were taken into account to rule out possible causes of the birth defects. These included smoking and drinking, the mother's age, how long she had lived in her village, and her race. These all proved statistically insignificant.

The authors believe that their study highlights the importance of educating people in high-risk malaria areas about the dangers of DDT.

Trigger of Deadly Food Toxin Discovered

A toxin produced by mold on nuts and grains can cause liver cancer if consumed in large quantities. University of California, Irvine, researchers for the first time have discovered what triggers the toxin to form, which could lead to methods of limiting its production.

Because of lax or nonexistent regulation, 4.5 billion people in developing countries are chronically exposed to vast amounts of this toxin, called aflatoxin—often hundreds of times higher than safe levels. In places such as China, Vietnam, and South Africa, the combination of aflatoxin and hepatitis B virus exposure increases the likelihood of liver cancer occurrence by 60 times, and toxin-related cancer causes up to 10% of all deaths in those nations.

"It's shocking how profoundly these molds can affect public health," said Sheryl Tsai, UCI molecular biology & biochemistry, chemistry, and pharmaceutical sciences associate professor and lead author of the study, which appears in a recent issue of Nature.

Aflatoxin can colonize and contaminate nuts and grains before harvest or during storage. The US Food and Drug Administration considers it an unavoidable food contaminant but sets maximum allowable limits.

The toxin wreaks havoc on a cancer-preventing gene in humans called p53. Without p53 protecting the body, aflatoxin can compromise immunity, interfere with metabolism, and cause severe malnutrition and cancer.

Tsai, graduate student Tyler Korman, and undergraduate Oliver Kamari-Bidkorpeh, along with Johns Hopkins University researchers, found that a protein called PT is critical for aflatoxin to form in fungi. Previously, scientists didn't know what prompted the toxin's growth.

"The protein PT is the key to making the poison," Tsai said. "With this knowledge, perhaps we could kill the PT with drugs, inhibiting the mold's ability to make aflatoxin."

Destroying the mold—rather than just the PT—is the traditional method of decontamination, but it's expensive, costing hundreds of millions of dollars worldwide.