Past Week in Nutrition Science (March 4th–11th)

This is an overview of interesting nutrition research published from Friday, March 4th, to Friday, March 11th, 2016.

Woman Holding Avocado Over Eye

Research Reviews

In the past week, we reviewed two articles: one from the New England Journal of Medicine, and the other from PLOS ONE.

Review: Eating Peanuts Early On Helps Prevent Allergy.

Article: Effect of Avoidance on Peanut Allergy after Early Peanut Consumption.

Summary: This was a follow-up study of a trial examining the effects of eating peanuts from early age on the risk of becoming allergic to peanuts.

The trial found that eating peanuts from early age reduced the risk of peanut allergy. This follow-up study showed that the protective effect was maintained over a year.

Review: Weight Loss Changes the Gut Microbiota.

Article: Characterization of the Gut Microbial Community of Obese Patients Following a Weight-Loss Intervention Using Whole Metagenome Shotgun Sequencing.

Summary: This observational study examined changes in the gut microbiota during and after a weight loss trial.

Although the microbiota remained quite stable during the weight loss trial, the counts of some types of bacteria changed significantly. The study also found that some bacteria could be used to predict weight loss success.

New Research From Around the World

Quite a few interesting papers came to our attention this week. We have summarized the most interesting or relevant papers, categorized by subject.

1. Obesity and Weight Loss

Introduction of complementary feeding before 4 months of age increases the risk of childhood overweight or obesity: a meta-analysis of prospective cohort studies.

This meta-analysis of observational studies suggests that infants younger than four months should only be fed breastmilk, since eating other foods early on may increase the risk of weight gain or obesity later.

Vegetarianism and cardiometabolic disease risk factors: Differences between South Asian and American adults.

This observational study found that American vegetarians generally ate healthier food, compared to Asian vegetarians. However, both populations were less likely to be overweight or obese than non-vegetarians.

Inverse association between altitude and obesity: A prevalence study among Andean and low-altitude adult individuals of Peru.

This observational study in Peruvian adults found that those who lived high in the mountains were at a lower risk of gaining weight or becoming obese, compared to those who lived closer to sea level.

Antiobesity effect of Pediococcus pentosaceus LP28 on overweight subjects: a randomized, double-blind, placebo-controlled clinical trial.

One previous study showed that the lactic acid bacterium, Pediococcus pentosaceusLP28 (LP28), reduced obesity and fatty liver in obese mice on a high-fat diet.

This randomized, controlled trial in overweight humans showed that supplementing with heat-killed LP28, once a day for 12 weeks, reduced BMI, body fat and waist circumference.

Effects of a mindfulness-based weight loss intervention in adults with obesity: A randomized clinical trial.

This randomized, controlled trial did not show any significant benefits from promoting mindfulness during a weight-loss program.

However, the authors concluded that further studies are needed to evaluate the effects of mindful eating on the long-term maintenance of weight loss and metabolic heath.

Maternal obesity, gestational diabetes, breastfeeding and childhood overweight at age 2 years.

This observational study indicates that children who have mothers who were overweight or obese before pregnancy, or gained excessive weight during pregnancy, are more likely to be overweight when they are two years of age.

The study also suggests that breastfeeding for 6 months or longer may reduce the child’s risk of gaining excessive weight until the age of two.

Does low-energy sweetener consumption affect energy intake and body weight? A systematic review, including meta-analyses, of the evidence from human and animal studies.

This systematic review and meta-analysis of randomized, controlled trials suggests that consuming low-calorie sweeteners does not lead to weight gain.

The evidence indicates that choosing low-calorie sweeteners instead of sugar leads to lower calorie intake and body weight in both adults and children.

2. Blood Sugar Control and Diabetes

Mechanisms linking the gut microbiome and glucose metabolism.

Type 2 diabetes is associated with an imbalance in the gut microbiota (dysbiosis). Restoring the gut microbiota by changing the diet or supplementing with probiotics may improve blood sugar control.

This scientific review discusses the potential of treating type 2 diabetes by targeting the gut microbiota. It also points out possible explanations for the link between the gut microbiota, type 2 diabetes and other metabolic disorders.

Effect of soy protein isolate preload on postprandial glycemic control in healthy humans.

This experiment showed that eating soy protein, 20 or 40 grams, before eating carbs (75 g of glucose) improved the blood sugar response by increasing the production of insulin and delaying stomach emptying.

3. Heart Health

Excess protein intake relative to fiber and cardiovascular events in elderly men with chronic kidney disease.

This observational study in elderly men with chronic kidney disease indicates that when protein intake is high, relative to fiber, their risk of heart disease is higher than when the ratio of protein to fiber is lower.

4. Cancer

Dietary Fiber Intake in Young Adults and Breast Cancer Risk.

This observational study suggests that fiber intake during adolescence and early adult life may reduce the risk of breast cancer.

Glycemic Index, Glycemic Load, and Lung Cancer Risk in Non-Hispanic Whites.

This observational study indicates that eating lots of foods high on the glycemic index may increase the risk of lung cancer.

5. Appetite and Eating

Protein-Enriched Liquid Preloads Varying in Macronutrient Content Modulate Appetite and Appetite-Regulating Hormones in Healthy Adults.

This randomized trial examined the effects of consuming liquids varying in protein, carbs and fat on appetite. It showed that protein reduced appetite more than carbs and fat.

Overeating at dinner time among Japanese workers: Is overeating related to stress response and late dinner times?

This observational study in Japanese men suggests that psychological stress makes them more likely to overeat at dinner.

6. Liver Health

Changes in the Intestinal Microbiome and Alcoholic- and Non-alcoholic Liver Diseases—Causes or Effects?

Fatty liver disease is characterized by the accumulation of fat in liver cells. It is often associated with heavy alcohol consumption, obesity and metabolic syndrome.

Severe fatty liver disease is associated with inflammation and may progress to cirrhosis. This review discusses the potential role of the microbiota in fatty liver disease, and the possibility of treating it by targeting the microbiota.

7. Muscles and Physical Performance

Ratio of Dietary n-3 and n-6 Fatty Acids—Independent Determinants of Muscle Mass—in Hemodialysis Patients with Diabetes.

This observational study in patients with kidney failure and type 2 diabetes examined the association of fatty acids and muscle mass.

It found that a high intake of omega-3 fat, relative to omega-6, was significantly linked with higher muscle mass.

8. Arthritis

Intake of high-fructose corn syrup sweetened soft drinks, fruit drinks and apple juice is associated with prevalent arthritis in US adults, aged 20–30 years.

This observational study suggests that drinking lots of soft drinks sweetened with high-fructose corn syrup may increase the risk of arthritis in young US adults.

According to the enFruAGEs hypothesis, poor fructose absorption due to excess free fructose may lead to inflammation in joints.

Vitamin D Supplementation, Tibial Cartilage Volume, and Symptomatic Knee Osteoarthritis.

A few observational studies suggest that supplementing with vitamin D may improve symptoms of knee osteoarthritis, but not all studies agree.

This randomized, controlled trial in 413 people with knee osteoarthritis and low circulating levels of vitamin D found that supplementing with 50,000 IU of vitamin D, every month for two years, did not increase cartilage or reduce knee pain.

9. Allergies

Randomized Trial of Introduction of Allergenic Foods in Breast-Fed Infants.

This randomized trial in breast-fed infants examined the effects of the early introduction of six allergenic foods — peanuts, eggs, cow’s milk, sesame, whitefish and wheat — on the risk of developing allergy to these foods.

The study suggests that when children start eating peanuts and eggs at three months of age, they have less risk of developing allergies when they are 1–3 years old, as long they eat at least 2 grams per week.

10. Skin Health

Synbiotics for Prevention and Treatment of Atopic Dermatitis. A Meta-analysis of Randomized Clinical Trials.

Eczema, is a chronic skin condition characterized by itchy, dry and red skin.

This meta-analysis of randomized trials indicates that taking synbiotics — the combination of probiotics and prebiotics — may help treat eczema. Synbiotics with several different types of bacteria appear to be the most effective.

11. Sleep

Dinner fat intake and sleep duration and self-reported sleep parameters over five years: findings from the Jiangsu Nutrition Study of Chinese adults.

This observational study in Chinese adults showed that a high fat intake at dinner was linked with shorter sleep duration. Similarly, a high fat intake at breakfast was associated with a reduced risk of falling asleep during the daytime.

12. Pain

Tolerance and efficacy of a polyamine-deficient diet for the treatment of perioperative pain.

Polyamines are a group of nutrients that appear to be necessary for cell division. However, if their levels are too high, they may bind to pain receptors, causing pain.

They are produced by the body in small quantities, but we also get them from the diet. This randomized trial found that eliminating polyamines from the diet reduced self-rated pain after surgery.