The following articles are being published in the September 2012 issue of The Journal of Nutrition, a publication of the American Society for Nutrition. Summaries of the selected articles appear below; the full text of each article is available by clicking on the links listed. Manuscripts published in The Journal of Nutrition are embargoed until the article appears online either as in press (Articles in Press) or as a final version. The embargoes for the following articles have expired.

Low-protein diet during pregnancy may increase blood sugar in later life

Higher circulating antioxidant levels found to be associated with lower risk for metabolic syndrome in teens

Higher-fat diets and wine related to lower risk for abdominal obesity in women

Low-protein diet during pregnancy may increase blood sugar in later life

Maternal malnutrition during pregnancy has long been known to impact important indicators of newborn health, such as prematurity and low birth weight. There is also growing evidence that poor maternal nutrition may have more long-term effects such as increasing an infant's chance of developing obesity, heart disease, and type 2 diabetes during adulthood. Although scientists are still unraveling exactly how this works, many suspect that some of these long-term effects have to do with regulation of gene expression. In other words, poor nutrition during fetal life might cause some genes to be permanently more active and others to be functionally silenced. This phenomenon, called epigenetics, is in fact a relatively "hot topic" among scientists trying to understand how what we eat influences our health. In a paper published in the September 2012 issue of The Journal of Nutrition, researchers from China and Germany report their findings that maternal protein restriction during pregnancy can indeed influence an offspring's glucose homeostasis via epigenetic mechanisms - at least in pigs.

The researchers were specifically interested in understanding the effect of early dietary protein restriction on activation (or inactivation) of the gene coding for glucose-6-phosphatase (G6PC), a protein needed by the liver to make glucose during periods of low blood sugar (hypoglycemia). Female pigs were fed a diet containing either 6 or 12% protein prior to pregnancy through delivery. Immediately after birth, 2 representative piglets (1 male and 1 female) were removed from the litter and sacrificed. Blood was analyzed for a variety of hormones (e.g., cortisol and glucagon) and metabolites (e.g., glucose and triglycerides), whereas the liver samples were analyzed for glycogen (a hormone released during hypoglycemia) and a variety of factors related to G6PC production and activity.

As expected, piglets born to mothers consuming low-protein diets were smaller at birth than those born to well-nourished mothers, and males weighed consistently more than females. Male piglets born to protein-deficient sows had lower blood glucose concentrations, higher liver G6PC gene expression, and enhanced G6PC activity compared to those born to well-nourished sows. This effect appeared to be related to several complementary epigenetic modifications. The authors concluded that consuming a low-protein diet during pregnancy may predispose male offspring to increased G6PC activity - possibly contributing to adult onset of elevated blood sugar (hyperglycemia). This is important because hyperglycemia is a common and sometimes serious condition, being related to type 2 diabetes and metabolic syndrome and their associated negative health sequelae.

Reference Jia Y, Cong R, Li R, Yang X, Sun Q, Parvizi N, Zhao R. Maternal low-protein diet induces gender-dependent changes in epigenetic regulation of the glucose-6-phosphatase gene in newborn piglet liver. Journal of Nutrition 142:1659-1665, 2012.

For More Information To contact the corresponding author, Dr. Ruqian Zhao, please send an e-mail to zhao.ruqian@gmail.com.

Higher circulating antioxidant levels found to be associated with lower risk for metabolic syndrome in teens

Over the past decade, inflammation has become the new buzzword in terms of what may trigger many serious health conditions such as cancer, type 2 diabetes, and cardiovascular disease. Indeed, chronic inflammation appears to play a key role in many of the chronic diseases facing our aging population. One area of intense interest is the relation between anti-inflammatory dietary compounds and the risk of developing metabolic syndrome, a potentially serious condition characterized by abdominal obesity ("apple-shaped" body), hypertension, high blood sugar, and unhealthy blood lipid levels. As oxidative stress can lead to inflammation, antioxidant nutrients (e.g., vitamin C, vitamin E) and other food-borne substances (e.g., carotenoids) are theoretically anti-inflammatory as well. Indeed, studies have suggested that (1) people with metabolic syndrome tend to be in a state of chronic inflammation, and (2) higher consumption of anti-inflammatory/antioxidant nutrients might be protective in this regard. However, these relations have not been investigated in adolescents - a group with increasing risk for metabolic syndrome. In a paper published in the September 2012 issue of The Journal of Nutrition, researchers report their finding that higher intake of dietary antioxidants is likely related to lower risk for metabolic syndrome in this population as well.

Data from this study were drawn from the National Health and Examination Surveys (NHANES), a nationally-representative epidemiologic investigation of nutrition and health that has been conducted by the US Centers for Disease Control and Prevention (CDC) since the early 1960s. For this particular investigation, data from adolescents aged 12-19 years from 2001-2006 were analyzed. Specifically, diagnosis of metabolic syndrome was related to a variety of measures reflecting antioxidant status (e.g., serum levels of vitamin C, vitamin E, and the carotenoids) and antioxidant intake (e.g., daily vitamin C consumption).

Results indicate that 7% of the boys and 3% of the girls studied had metabolic syndrome, and girls had consistently higher circulating levels of vitamin C, vitamin E, and β-carotene (a form of carotenoid). In both sexes, teens with metabolic syndrome had lower serum carotenoid concentrations and higher levels of chronic inflammation compared with their unaffected counterparts. They found somewhat similar results for vitamin C, but not vitamin E. However, the researchers were unable to document relationships between dietary antioxidant intake and risk for metabolic syndrome - likely highlighting the inaccuracies inherent in estimating nutrient intake. The authors concluded, "Future nutritional interventions with recommendation for appropriate dietary intakes should be conducted to assess the utility of modifying serum concentration of antioxidants."

Reference Beydoun MA, Canas JA, Beydoun HA, Chen X, Shroff MR, Zonderman AB. Serum antioxidant concentrations and metabolic syndrome are associated among US adolescents in recent national surveys. Journal of Nutrition 142:1693-1704, 2012.

For More Information To contact the corresponding author, Dr. May Beydoun, please send an e-mail to baydounm@mail.nih.gov.

Higher-fat diets and wine related to lower risk for abdominal obesity in women

Although many popular books, magazines, and television personalities would like us to think that eating certain foods can independently protect us from poor health, this approach is clearly too simplistic. Indeed, to get all the nutrients we need, eating a variety of foods is necessary, and it is this combination of foods and their associated nutrients that help determine our overall health. Furthermore, both genetics and other lifestyle factors (e.g., activity level, smoking) can interact with our food choices to influence health. For example, eating a well-balanced diet in moderate proportions may lower risk for heart disease in most people, but choosing to smoke cigarettes can somewhat negate these otherwise healthy decisions. Recent increases in the US obesity rates and related negative health outcomes (e.g., hypertension) have garnered much-needed attention to understanding better how our health can be affected by this "big picture" that includes diet, lifestyle choices, and genetics. In a study published in the September 2012 issue of The Journal of Nutrition, researchers describe what they found when exploring the relationships among dietary patterns, body fat distribution, smoking, and metabolic syndrome - a complex and unhealthy condition characterized by abdominal obesity, hypertension, elevated blood sugar, and unhealthy blood lipid levels.

The research was conducted as part of the Framingham Offspring/Spouse Study, initiated in 1971 in Framingham, Massachusetts, as a follow-up to the Framingham Heart Study which has investigated risk factors for cardiovascular disease and other health problems since 1948. In brief, 1146 women (~49 years old) with no history of cardiovascular disease, diabetes, cancer, or metabolic syndrome were followed for ~7 years. At the start of the study, women provided information concerning their dietary intakes. Additionally, and after every ~4 years, they also underwent physical examinations to document important variables related to disease risk, such as body weight, hypertension, blood lipids, medication use, smoking habits, and physical activity. Dietary patterns were characterized based upon the women's habitual food intake. Both overall healthfulness and content of specific components (e.g., fat) were evaluated.

The research team found that people consuming higher-fat diets and those characterized as including wine and "moderate eating" were less likely to develop abdominal obesity (apple-shaped body fat distribution) than people who consumed diets high in "empty" calories (foods with calories but few nutrients). For instance, people who tended to eat higher-fat diets were 52% less likely to have abdominal obesity than those choosing predominantly empty-calorie foods. However, none of the eating patterns studied appeared to be related to risk for metabolic syndrome, and the relationship between eating pattern and abdominal obesity was consistent regardless of whether a person did or did not smoke.

Reference Kimokoti RW, Gona P, Zhu L, Newby PK, Millen BE, Brown LS, D'Agostino RB, Fung TT. Dietary patterns of women are associated with incident abdominal obesity but not metabolic syndrome. Journal of Nutrition 142:1720-1727, 2012.

For More Information To contact the corresponding author, Dr. Ruth Kimokoti, please send an e-mail to ruth.kimokoti@simmons.edu.

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