Past Week in Nutrition Science (May 13th–20th)

This is an overview of interesting nutrition research published from Friday, May 13th to Friday, May 20th, 2016.

Here are some of the more interesting findings this week:

Artificial sweetener use in pregnancy linked to obesity in the child.
High-fat dairy products linked to a major reduction in type 2 diabetes risk.
The benefits of eating plenty of unprocessed fruits and vegetables.
Plant omega-3s don’t lower heart disease risk.
Polyunsaturated fats may improve heart disease risk factors more than monounsaturated fats.
How probiotic use affects cancer risk.
How weight stigma makes overweight people anxious and causes them to eat more.

Female Indian Doctor Holding Apple

Research Reviews

This week we reviewed two papers: one on the association between artificial sweetener consumption during pregnancy and obesity in the child and another about the links between dairy fat consumption and type 2 diabetes.

Review: Artificial Sweeteners in Pregnancy and Obesity in The Child.

Article: Association Between Artificially Sweetened Beverage Consumption During Pregnancy and Infant Body Mass Index.

Summary: This observational study found that a high intake of artificial sweeteners during pregnancy was linked to an increased risk of obesity in the child.

Review: High-Fat Dairy Linked to Drastically Reduced Diabetes Risk.

Article: Circulating Biomarkers of Dairy Fat and Risk of Incident Diabetes Mellitus Among Men and Women in the United States in Two Large Prospective Cohorts.

Summary: This observational study suggested that eating a lot of dairy fat may protect against type 2 diabetes.

New Research from Around the World

Many new papers came to our attention this week. Here are summaries of the most interesting or relevant studies, categorized by subject.

1. Obesity and Weight Loss

Distribution of energy intake throughout the day and weight gain: a population-based cohort study in Spain.

This observational study showed that higher calorie intake at lunch was associated with a lower risk of weight gain. The findings suggest that the timing of calorie intake during the day may play a role in obesity.

Changes in water and sugar-containing beverage consumption and body weight outcomes in children.

This observational study in children found that water consumption (1 glass/day) was not linked to body mass index.

However, the findings suggest that water may replace sugar-sweetened beverages, which were associated with an increased body mass index and a greater risk of obesity.

Prevalence of overweight and obesity among children and adolescents with intellectual disabilities: a systematic review and meta-analysis.

This systematic review and meta-analysis of observational studies suggests that adolescents with intellectual disabilities are at 1.8 times greater risk of obesity, compared to typical adolescents.

Does neighborhood fast-food outlet exposure amplify inequalities in diet and obesity? A cross-sectional study.

This observational study suggests that easy access to fast food outlets, combined with low education levels, may predispose people to a greater risk of gaining weight and becoming obese.

Low energy intake plus low energy expenditure (low energy flux), not energy surfeit, predicts future body fat gain.

This observational study indicates that low calorie expenditure due to low metabolic rate or physical activity predicts future weight gain more than excess calorie intake.

2. Heart Health

Adult Intake of Minimally Processed Fruits and Vegetables: Associations with Cardiometabolic Disease Risk Factors.

This observational study in adults without heart disease or metabolic disorders found that a high intake of minimally processed fruits and non-starch vegetables, relative to total food intake, was associated with less body fat and lower insulin levels.

Acute effects of quercetin-3-O-glucoside on endothelial function and blood pressure: a randomized dose-response study.

Quercetin-3-O-glucoside, also known as isoquercetin, is a flavonoid antioxidant found in many fruits and vegetables.

This randomized controlled study showed that one dose of isoquercetin, ranging from 50 to 400 mg, has no effect on blood pressure or blood vessel function.

Dietary intake and adipose tissue content of α-linolenic acid and risk of myocardial infarction: a Danish cohort study.

Previous studies indicate that a high dietary intake of omega-3 alpha-linolenic acid may reduce the risk of heart disease, but their findings are inconsistent.

This prospective observational study indicates that alpha-linolenic acid has no significant effects on the risk of heart attacks.

Poly is more Effective than Mono – Unsaturated Fat For dietary management IN the Metabolic Syndrome: The MUFFIN Study.

This was a randomized controlled study in middle-aged people with metabolic syndrome who followed a diet enriched with either monounsaturated fat (MUFA) or polyunsaturated fat (PUFA) for half a year.

The study found that following a diet high in PUFA caused a greater reduction in triglycerides, blood pressure and blood vessel function than a diet rich in MUFA.

3. Cancer

The Potential Role of Probiotics in Cancer Prevention and Treatment.

This review discusses the possible use of probiotics in the prevention and treatment of cancer. The authors conclude that supplementing with probiotics may reduce diarrhea in patients undergoing radio- or chemotherapy.

Supplementing with probiotics may also promote general health, helping to prevent lifestyle-related cancer, as well as other chronic diseases.

Alcohol Intake is Associated with Increased Risk of Squamous Cell Carcinoma of the Skin: Three US Prospective Cohort Studies.

This observational study showed that alcohol intake was associated with an increased risk of skin cancer.

Specifically, each additional drink (12.8 grams of ethanol) was linked to a 22% increased risk of a type of skin cancer known as cutaneous squamous cell carcinoma.

4. Appetite and Eating

Weight stigma and eating behavior: A review of the literature.

Overweight and obese people are sometimes frowned upon. This form of social devaluation is known as weight stigma. It is a source of anxiety for many people, but not all obese people experience it.

This review suggests that experiencing weight stigma may worsen unhealthy eating behaviors and reduce people’s motivation to diet and exercise.

Paved with good intentions: Paradoxical eating responses to weight stigma.

Some people believe that overweight and obese people could easily lose weight if they really wanted to. They consider obese people to be greedy, excessive and selfish, rather than victims of a disorder.

This review concludes that weight stigma may promote overeating and reduce people’s interest in losing weight. The findings suggest that low self-esteem and social discrimination may decrease motivation.

This observational study found that weight-related teasing reduced people’s chance of successfully maintaining their weight after weight loss.

It suggests that the anxiety and low self-esteem associated with weight-related teasing made people more prone to emotional eating, which is the tendency to overeat in response to negative emotions.

Internalized weight stigma moderates eating behavior outcomes in women with high BMI participating in a healthy living program.

This study in obese women examined the effect of self-perceived weight stigma on dysfunctional eating behavior after a weight loss program.

The study found that women who experienced a lot of weight stigma were less likely to change their eating behavior, compared to women who perceived less weight stigma.

Increased colonic propionate reduces anticipatory reward responses in the human striatum to high-energy foods.

Short-chain fatty acids, such as butyrate and propionate, are formed in the colon when intestinal bacteria ferment dietary fiber. Animal research indicates that increased production of propionate may reduce calorie intake.

This randomized controlled trial supports earlier research suggesting that high propionate production in the colon may reduce reward-driven eating behavior in humans.

5. Skin Health

Consuming High-Carotenoid Fruit and Vegetables Influences Skin Yellowness and Plasma Carotenoids in Young Women: A Single-Blind Randomized Crossover Trial.

Carotenoids are a class of antioxidant pigments found in plants. Eating lots of carotenoid-rich fruit and vegetables leads to their accumulation in human skin, making it more yellow.

This randomized controlled trial showed that a diet high in carotenoid-rich fruits and vegetables (7 servings a day for one month) led to significantly greater skin yellowness, compared to a diet consisting of low-carotenoid fruits and vegetables.

6. Healthy Aging

Pork and Chicken Meals Similarly Impact on Cognitive Function and Strength in Community-Living Older Adults: A Pilot Study.

This study in elderly people showed that eating pork meals 4 times per week for 3 months did not improve strength, physical performance or mental function, compared to similar meals containing chicken.

7. Vitamins, Minerals and Other Nutrients

Gluten free diet and nutrient deficiencies: a review.

The only treatment for gluten intolerance is lifelong avoidance of gluten-containing foods. This review examined the possible nutrient insufficiences of gluten-free diets.

Some nutrients may be of short supply, especially fiber, vitamin D, vitamin B12, folate, iron, zinc, magnesium and calcium. However, many of these nutrient insufficiencies are not specific to gluten-free diets but to people’s diets in general.

Free 25-hydroxyvitamin D is low in obesity, but there are no adverse associations with bone health.

25-hydroxyvitamin D (25(OH)D) is the main circulating form of vitamin D in the body. Its levels are believed to accurately reflect people’s vitamin D status.

This observational study in normal-weight, overweight and obese men and women showed that 25(OH)D levels decrease with a higher body mass index. This is supported by previous studies, but the reason for this association is still unknown.