Past Week in Nutrition Science: This is an overview of interesting research articles published from Friday, Oct 16th, to Friday, Oct 23rd.
Past Week in Nutrition Science (Feb 21th–Feb 27th)
Research Reviews
This week we reviewed two research papers, one from the American Journal of Clinical Nutrition and one from Obesity.
Monday
Link: The Paleo Diet May Help Fight Metabolic Syndrome.
Study: Paleolithic nutrition for metabolic syndrome: systematic review and meta-analysis.
Summary: This was a meta-analysis of randomized controlled trials that compared the paleo diet with other dietary patterns.
The study showed that the paleo diet may have moderate benefits for metabolic syndrome, compared to diets based on official nutrition guidelines.
Wednesday
Link: Probiotics May Help Prevent Weight Gain.
Summary: This randomized controlled trial examined whether a broad-spectrum probiotic supplement could reduce weight gain on a high-fat, high-calorie diet.
The study showed that people who took a probiotic supplement gained significantly less weight than those who took the placebo.
Other New Research From Around the World
Tons of new studies were published this week. Many journals released new papers online and a new issue of the British Journal of Nutrition came out.
Here is an overview of the most interesting nutrition research, categorized by subject.
Obesity and Weight Loss
This paper presented results from the LIPOGAIN study, a randomized trial that compared the effects of eating high amounts of saturated fats (SF) or polyunsaturated fats (PF).
SF caused greater total fat gain and accumulation in the liver and belly than PF, even though the weight gain was the same. It was hypothesized that overfeeding with PF may be associated with higher insulin sensitivity than overfeeding with SF.
Effects of overweight and obesity on motor and mental development in infants and toddlers.
This observational study suggests that obese, young children are more likely to have delays in mental and motor development than their normal-weight counterparts.
Lean and obese dietary phenotypes: differences in energy and substrate metabolism and appetite.
This study examined the effects of a high-fat meal on appetite and metabolic profiles in lean, high-fat consumers; lean, low-fat consumers; and obese, high-fat consumers (OHF).
Appetite ratings were similar for all, but the LHF group had greater fat burning capacity than the LLF group. The hunger/appetite hormones ghrelin and PYY changed more in the lean groups, but this response was weaker in the OHF group.
This was a meta-analysis of randomized controlled trials comparing the efficacy of low-carb and low-fat diets for weight loss. It concluded that both diets lead to significant weight loss. However, low-carb diets seem to be slightly more effective.
Metabolic Syndrome
This observational study suggests that a diet rich in carotenoids may reduce the risk of metabolic syndrome in Japanese people.
This observational study suggests that good vitamin D status may reduce the risk of high blood pressure, poor blood lipid profile and metabolic syndrome.
Magnesium status and the metabolic syndrome: a systematic review and meta-analysis.
This meta-analysis of observational studies showed that high magnesium levels are associated with reduced risk of metabolic syndrome. However, there was a large amount of variability between individuals.
Heart Health
This rat study found that vinegar may lower blood pressure. The effect is caused by the acetic acid in vinegar.
This study showed that long-term supplementation with rice bran extract lowers cholesterol levels and prevents clogged blood vessels in mice that are predisposed to atherosclerosis.
Blood Sugar Control and Type 2 Diabetes
The glycaemic outcomes of Cinnamon, a review of the experimental evidence and clinical trials.
This reviewed the evidence of cinnamon’s effect on blood sugar control and type 2 diabetes. It concluded that cinnamon may be useful for treating type 2 diabetes, when combined with mainstream treatment and other healthy lifestyle strategies.
However, the evidence is inconclusive, and the high coumarin content of cassia cinnamon is a health concern. Ceylon cinnamon is a safer option.
This systematic review concludes that there is no optimal diet for treating type 2 diabetes in overweight and obese people. Losing weight is crucial, but the dietary strategy is less important.
Urinary isoflavonoids and risk of type 2 diabetes: a prospective investigation in US women.
Isoflavonoids, or isoflavones, are plant compounds found in legumes, especially soybeans. Two of the most common isoflavonoids in soy are daidzein and genistein.
This observational study found that the amount of daidzein and genistein in urine was associated with lower risk of type 2 diabetes in US women.
Cancer
Anthocyanins are antioxidant plant compounds found in many colorful fruits and vegetables. After they are absorbed from the digestive tract, they are metabolized by the liver.
This study indicates that anthocyanin metabolites, isolated from the blood of healthy adults, may help prevent the spread of pancreatic cancer cells.
A Trial of Calcium and Vitamin D for the Prevention of Colorectal Adenomas.
Previous observational studies indicate that high intake of vitamin D or calcium may reduce the risk of colorectal cancer.
This double-blind, randomized controlled trial found that daily supplementation with calcium (1200 mg), vitamin D3 (1000 IU) or a combination of both did not reduce the risk of recurrent colorectal cancer during a period of 3 to 5 years.
An update on Curcuma as a functional food in the control of cancer and inflammation.
Curcumin is a plant compound found in the Indian spice turmeric. This review discusses recent studies on the potential use of curcumin in the treatment of inflammation and cancer. Overall, its efficacy is considered questionable.
Egg and cholesterol intake and incident type 2 diabetes among French women.
This observational study in French women found that high cholesterol intake was associated with an increased risk of type 2 diabetes. On the other hand, egg consumption was not associated with type 2 diabetes.
Digestive Health
This randomized controlled trial found that supplements of the probiotic bacteriumBifidobacterium animalis can increase the frequency of bowel movements.
This suggests that B. animalis may improve digestive health and reduce the risk of constipation.
Brain Health and Function
Anthocyanins are a group of antioxidant polyphenols responsible for the color of many fruits and vegetables.
This randomized controlled trial found that drinking 200 ml of cherry juice, rich in anthocyanins, daily for 12 weeks, may improve memory in older people with mild or moderate dementia. Juice that was low in anthocyanins did not have similar effects.
This observational study indicates that long-term adherence to an overall healthy diet may reduce the risk of depression.
The impact of gut microbiota on brain and behaviour: implications for psychiatry.
This review suggests that certain psychiatric disorders might be treated by changing the bacterial community in the gut.
Gluten-free and casein-free diets in the therapy of autism.
This review concludes that most studies on the efficacy of gluten-free and casein-free diets for treating autism are poorly designed. There is limited evidence to support the use of gluten-free and casein-free diets in the treatment of autism.
The beneficial effects of berries on cognition, motor behaviour and neuronal function in ageing.
This study of rats suggests that eating berries may improve motor function and cognition, especially memory.
Respiratory Health
This cross-sectional observational study suggests that high consumption of sugary soft drinks, sweetened with high-fructose corn syrup, may contribute to chronic bronchitis.
Infections and Immune Health
IgY antibodies in human nutrition for disease prevention.
This review hypothesizes that IgY antibodies, found in egg yolks, may be useful in the treatment or prevention of bacterial infections in the digestive system.
Allergies and Intolerance
The only known treatment for celiac disease is the gluten-free diet. However, this small, cross-sectional observational study indicates that celiac disease patients adhering to a gluten-free diet had low folate intake and low levels of folate in blood.
Hearing
Low-fat and low-protein diets are associated with hearing discomfort among the elderly of Korea.
This observational study showed that low protein and fat intake was associated with hearing problems among elderly people.
Supplements
Emergency Department Visits for Adverse Events Related to Dietary Supplements.
This study estimated that dietary supplements are responsible for 23,000 emergency department visits every year in the US. This includes 2154 hospitalizations. Weight loss supplements were most often involved.
Quercetin is one of the most common antioxidant flavonoids found in plant foods. It is also sold as a supplement.
This randomized controlled trial showed that quercetin aglycone, found in the skin of onions, is much better absorbed than quercetin dihydrate, found in many supplements.
