Past Week in Nutrition Science: This is an overview of interesting nutrition research published from Friday, January 22nd, to Friday, January 29th, 2016.
Past Week in Nutrition Science (Jan 22nd–Jan 29th)
We reviewed two research articles in the past week: one from the European Journal of Nutrition, and the other from Advances in Nutrition.
Summary: This small, randomized, controlled trial examined the effects of a high-fat diet and a low-fat diet on insulin sensitivity.
The study indicates that a diet very high in fat lowers insulin sensitivity. However, the results may not be of much relevance in a real-life setting, because the amounts of fat on the high-fat diet far exceeded normal intakes.
Summary: This review article provides an overview of the evidence linking the gut bacteria with obesity, metabolic diseases and diet.
New Research From Around the World
Numerous papers came out this week, many of which were published ahead of print.
As usual, we provide a summary of the most interesting or relevant papers, organized by subject.
- Obesity and Weight Loss
- Metabolic Syndrome
- Blood Sugar Control and Diabetes
- Heart Health
- Brain and Mental Health
- Digestive Health
- Kidney Health
- Lung Health
- Immune Health
- Healthy Aging and Longevity
- Nutrients, Vitamins and Minerals
1. Obesity and Weight Loss
This observational study showed that those who eat the highest amounts of whole grains in the US are less likely to be overweight or obese. Also, they have better nutrient and fiber intakes.
This randomized trial examined whether the speed of weight loss has any effects on weight regain after dieting stops.
Weight regain was similar among those who lost weight rapidly and those who had a slower weight loss. However, losing weight rapidly caused a greater reduction in lean mass, which was associated with weight regain later on.
This observational study suggests that drinking sugar-sweetened beverages increases people’s chance of gaining fat in the abdominal cavity (visceral fat). Drinking diet soda had no such effects.
This randomized trial compared the effects of high and low protein intake on changes in mass during 4 weeks of intense exercise and 40% calorie reduction.
Supplementing with high amounts of protein, 2.4 grams/kg (about 2.2 lbs) per day, caused greater fat loss and a higher gain in lean mass, compared to lower amounts of protein, or 1.2 grams/kg per day.
Flavonoids are a large group of antioxidants found in plant foods. This observational study suggests that a high intake of flavonoid-rich foods, such as fruits and vegetables, may protect against weight gain.
2. Metabolic Syndrome
This observational study suggests that eating high amounts of omega-3 fats and fish in young adulthood may reduce the risk of metabolic syndrome later in life. However, eating fried fish did not seem to have similar effects.
3. Blood Sugar Control and Diabetes
This review discusses the effects of vitamin K supplements on glucose metabolism, insulin sensitivity and the risk of type 2 diabetes.
This small, randomized trial suggests that eating hummus is better for blood sugar control than eating white bread.
4. Heart Health
This observational study indicates that eating breakfast regularly may protect against stroke in Japanese people. Conversely, skipping breakfast does not seem to increase the risk of coronary heart disease.
This observational study suggests that eating high amounts of red or processed meat increases the risk of death among patients with cancer in the lungs or upper digestive tract. This association was weaker for unprocessed red meat.
Lycopene is an antioxidant carotenoid found in high amounts in tomatoes, guavas and watermelons. This observational study suggests that getting high amounts of lycopene from the diet may reduce the risk of prostate cancer.
6. Brain and Mental Health
Previous studies suggest that trans fats may increase the risk of depression. This observational study indicates that a high intake of trans fats from margarine and baked products may interfere with the ability to think clearly under emotional stress.
This rat study showed that eating hazelnuts, 800 mg/kg/day for 1 week, may improve memory, reduce anxiety-related behavior and reduce inflammatory markers. However, human trials need to confirm these findings.
7. Digestive Health
This observational study suggests there are no specific dietary patterns associated with the risk of inflammatory bowel disease. However, a high intake of sugary drinks was a significant risk factor for those who had a low vegetable intake.
Additionally, there was a similar association for cases that occurred in the first two years after dietary assessment.
Crohn’s disease is an inflammatory bowel disease characterized by inflammation in the digestive tract. Some scientists believe that inflammatory bowel disease may be caused by an adverse change in the gut microbiota.
This study indicates that Crohn’s disease is associated with distinct types of bacteria, which vary depending on the location in the digestive tract. For example, high numbers of Fusobacterium were associated with Crohn’s disease in the ileum.
The incidence of inflammatory bowel disease (IBD) seems to be on the rise among children. This review discusses the available evidence regarding the role of nutrition and environmental factors in the development of IBD in children.
Children with autism or related disorders often have digestive problems. This observational study suggests that breastfeeding and late weaning may help prevent digestive problems for infants who are at a high risk of autism-spectrum disorders.
8. Kidney Health
This observational study indicates that eating probiotic yogurt frequently, or supplementing with probiotics, may reduce the risk of kidney disease.
9. Lung Health
Studies about asthma and vitamin D deficiency early in life have provided inconsistent results. This study suggests that the asthma risk of 3-year-old children is not affected by their mother’s vitamin D intake while pregnant.
This randomized, controlled trial in pregnant women examined the effects of vitamin D supplements on childhood asthma outcomes.
The study showed that 2,800 IU of vitamin D per day did not reduce the risk of asthma symptoms in the children, compared to supplementing with 400 IU/day.
10. Immune Health
An adequate zinc status is essential for the function of the immune system.
This randomized, controlled trial in elderly people showed that zinc supplementation, 30 mg per day for 3 months, improved immune function.
11. Healthy Aging and Longevity
Telomeres are sequences of DNA whose lengths are a marker of aging. Previous studies show that oxidative stress speeds up the shortening of the telomeres, whereas antioxidants delay the shortening.
This study in US adults also found that circulating levels of carotenoid antioxidants were significantly associated with longer telomeres in white blood cells.
This observational study suggests that eating high amounts of fruits and vegetables may reduce the risk of death from all causes.
12. Nutrients, Vitamins and Minerals
This study confirmed the popular belief that fat-reduced foods generally contain more sugar than their full-fat versions.