Nutrition News

Nutrition Updates
May 2008
Barbara Quinn, MS, RD, CDE

Experts continue to study the relationship between fruit juice consumption and the incidence of obesity in children and adolescents. This review assesses 9 cross-sectional and 12 longitudinal studies on this topic. Only three studies found a positive association between the consumption of fruit juice and obesity. Data supports consumption of 100 percent fruit juice in moderate amounts, according to this review.
http://ajl.sagepub.com/cgi/rapidpdf/1559827608317277v1.

Research on fructose and sucrose

• This short-term study on 34 men and women compared the metabolic effects of consuming beverages sweetened with high-fructose corn syrup (55 percent fructose and 45 percent glucose) versus those sweetened with sucrose (50 percent fructose and 50 percent glucose). Researchers found no substantial difference between HFCS- and sucrose-sweetened beverages on postprandial glucose, leptin, and ghrelin levels (endocrine signals of body weight regulation). However, both sucrose and HFCS had higher than expected effects on post-meal triacylglycerol (TG) levels. The authors urge more study to fully understand the metabolic effects of fructose-containing sugars.
  http://www.ajcn.org/cgi/content/abstract/87/5/1194
• Overfeeding pure fructose increased triglyceride and fasting glucose concentrations in male subjects more than females in this short study on 16 healthy volunteers.
  http://care.diabetesjournals.org/cgi/content/abstract/31/6/1254
• This meta-analysis of well-designed studies examined the impact of sucrose on the behavior of children. The analysis produced “no evidence” that sucrose has an adverse influence on the behavior of children, according the report published in Critical Reviews in Food Science and Nutrition, May 2008.
  http://www.informaworld.com/smpp/content~db=all?content=10.1080/10408390701407316

Update on screening pregnant women for gestational diabetes
The United States Preventive Services Task Force has recently updated the recommendations for screening pregnant women for gestational diabetes:
http://www.annals.org/cgi/content/abstract/148/10/759.

Phytosterols and omega-3 fats to treat high cholesterol
This 3-week randomized, double-blind, placebo-controlled trial studied the effects of phytosterol and/or (n-3) polyunsaturated fatty acid supplementation in 60 subjects with high blood lipids. Treatment with a combination of phytosterols and fish oils rich in (n-3) long-chain polyunsaturated fatty acids reduced plasma cholesterol, increased HDL cholesterol, and decreased plasma triglyceride levels to a greater extent than phytosterol treatment alone.
http://jn.nutrition.org/cgi/content/abstract/138/6/1086

What effects do various cooking methods have on the retention of minerals in potatoes?
This food science study found that boiling cubed and shredded potatoes decreased the potassium content by 50 and 75 percent respectively. Other results can be found at
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1750-3841.2008.00782.x?prevSearch=allfield%3A%28Jansky%29.

Alkaline-residue diets favor lean body mass
This intriguing study found a positive association between urinary potassium (a marker for potassium intake) and percent lean body mass in 384 healthy men and women ages 65 and older.
“Protein and cereal grains are metabolized to acidic residues, mainly sulfuric acid,” explain the authors. “Fruit and vegetables are metabolized to alkaline residues, mainly potassium bicarbonate.”
As we age, our kidneys become less able to excrete excess hydrogen ions (from acid-producing foods) which can lead to mild metabolic acidosis—a condition linked to muscle wasting.
Thus, conclude the authors, a higher intake of fruits and vegetables may help maintain lean body (muscle) mass by relieving the mild metabolic acidosis that occurs with the ingestion of a diet rich in protein, cereal grains, and other acid-producing foods. Find the details at:
http://www.ajcn.org/cgi/content/abstract/87/3/662.