Past Week in Nutrition Science (June 10th – June 17th)

This is our weekly selection of recently published nutrition research.

Here are some of the most interesting findings this week:

Synchronizing a weight-loss diet with the menstrual cycle may help women lose weight.
Supplementing with probiotics may help reduce the symptoms of depression.
Eating pre-packaged food portions is more effective for weight loss than self-selecting.
A very-low calorie diet can treat type 2 diabetes in some people. These benefits are sustained while following a weight-maintenance diet.
Supplementing with probiotics can reduce the duration of antibiotic-related diarrhea.
Sodium in urine is a very inaccurate marker of dietary salt intake.
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Research Reviews

This week, we reviewed two studies: one about the effectiveness of the Menstralean diet for weight loss and the other about probiotics and depression.

Review: Can the Menstralean Diet Help You Lose Weight?

Article: A weight-loss program adapted to the menstrual cycle increases weight loss in healthy, overweight, premenopausal women: a 6-mo randomized controlled trial.

Summary: This was a randomized controlled trial examining the effectiveness of a weight loss program synchronized with the phases of the menstrual cycle (Menstralean diet).

The Menstralean diet led to more weight loss than a conventional, calorie-reduced diet. However, the Menstralean diet also provided higher amounts of protein and the novelty of the program seems to have motivated the participants.

Review: Can Probiotics Help Reduce Depression?

Article: Clinical and metabolic response to probiotic administration in patients with major depressive disorder: A randomized, double-blind, placebo-controlled trial.

Summary: This randomized controlled trial examined the effects of probiotics on the symptoms of major depressive disorder. Supplementing with probiotics led to a significant improvement in depression, compared to a placebo.

New Research From Around the World

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

Obesity and Weight Loss
Blood Sugar Control and Diabetes
Heart Health
Cancer
Appetite and Eating
Brain and Mental Health
Digestive Health
Muscles and Physical Performance
Infections and Immune Health
Skin Health
Pregnancy and Infant Health
Longevity and Healthy Aging
Women’s Health
Vitamins, Minerals and Other Nutrients
1. Obesity and Weight Loss

Randomized clinical trial of portion-controlled prepackaged foods to promote weight loss.

This randomized controlled trial showed that people who got pre-packaged lunch and dinner portions during a weight-loss program lost more weight than those who selected their own food.

Effects of breast-feeding compared with formula-feeding on preterm infant body composition: a systematic review and meta-analysis.

This systematic review and meta-analysis of observational studies in preterm infants suggests that formula-feeding may promote a greater fat gain when they are 1-12 month old, compared to breastfeeding.

2. Blood Sugar Control and Diabetes

A high-fat, high-glycaemic index, low-fibre dietary pattern is prospectively associated with type 2 diabetes in a British birth cohort.

This observational study showed that following a diet that is high in fat, low in fiber and high in easily-digested carbs (sugar and starch) was associated with an increased risk of developing type 2 diabetes.

This dietary pattern was characterized by low intake of fruits, vegetables and whole-grain cereals. It also provided high amounts of white bread, fried potatoes and processed meat.

Very Low-Calorie Diet and 6 Months of Weight Stability in Type 2 Diabetes: Pathophysiological Changes in Responders and Nonresponders.

Very-low calorie diets (VLCD) can be used to treat type 2 diabetes in some people. This study examined whether the benefits of a VLCD were sustained when a group of diabetics went on a weight-stabilizing diet (WSD) after following a VLCD for 8 weeks.

During the 6 months of follow-up, 40% of the participants maintained their low blood sugar levels. These findings suggest that the benefits of a VLCD can be sustained while following a WSD for at least 6 months afterwards.

3. Heart Health

Dietary epicatechin intake and 25-y risk of cardiovascular mortality: the Zutphen Elderly Study.

Epicatechin is a flavonoid antioxidant found in plant foods, such as green tea, apples and cocoa. Studies suggest that high intake of epicatechin may reduce the risk of heart disease.

This observational study in elderly men showed that a high epicatechin intake was associated with a reduced risk of death from heart disease.

Whole-grain intake and total, cardiovascular, and cancer mortality: a systematic review and meta-analysis of prospective studies.

Studies examining the association of whole grain intake with the risk of death from disease have provided inconsistent results.

This systematic review and meta-analysis of observational studies suggests that eating a lot of whole-grain cereals may reduce the risk of death from heart disease and cancer.

Association of fish consumption and dietary intake of marine n-3 PUFA with myocardial infarction in a prospective Danish cohort study.

Myocardial infarction (MI) is when blood flow to the heart is disrupted.

This observational study indicates that a high intake of fatty fish is linked with a lower risk of MI. Specifically, eating relatively high amounts of fatty fish reduced the risk by 12% in men and 22% in women.

4. Cancer

Vitamin D and colorectal cancer: molecular, epidemiological and clinical evidence.

This review discussed the association of vitamin D with colon cancer. Some observational studies suggest that vitamin D may have some benefits, but this has not been proved in clinical trials.

Calcium intake and breast cancer risk: meta-analysis of prospective cohort studies.

Calcium is a dietary mineral found in high amounts in dairy products. This meta-analysis of observational studies concluded that a high intake of calcium may reduce the risk of breast cancer.

Coffee Drinking and Risk of Lung Cancer—A Meta-Analysis.

This meta-analysis of observational studies showed that drinking coffee is not associated with the risk of developing lung cancer, when tobacco smoking is taken into account.

5. Appetite and Eating

Sociodemographic and Behavioral Factors Associated with Added Sugars Intake among US Adults.

This observational study in US adults showed that a high intake of added sugar was linked with a number of other unhealthy lifestyle behaviors, such as low physical activity and smoking.

It was also more common among those who were younger, less educated or had a lower income.

6. Brain and Mental Health

Serum α-linolenic and other ω-3 fatty acids, and risk of disabling dementia: community-based nested case-control study.

Scientists have speculated that adequate intake of omega-3 fatty acids may reduce the risk of dementia by protecting neurons and improving the health of blood vessels delivering blood and oxygen to the brain.

This observational study found that levels of alpha-linolenic acid were associated with a reduced risk of developing severe dementia. However, other omega-3 fats were not significantly linked with dementia.

7. Digestive Health

Probiotic Administration in Infants With Gastroschisis: A Pilot Randomized Placebo-Controlled Trial.

Gastrochisis is a serious birth defect that seems to be on the rise in the US. In children with gastrochisis, some of the intestines poke out of the body through a hole in the abdominal wall.

This randomized controlled trial in infants with gastrochisis showed that probiotic supplementation had no effects on any clinical outcomes, including the length of their hospital stay.

Effectiveness of Lactobacillus helveticus and Lactobacillus rhamnosus for the management of antibiotic-associated diarrhoea in healthy adults: a randomised, double-blind, placebo-controlled trial.

Broad-spectrum antibiotics can disrupt the gut microbiota, resulting in overgrowth of undesirable bacteria and diarrhea. However, evidence suggests that supplementing with probiotics may be effective at preventing these side effects.

This 10-week, randomized controlled trial showed that supplementing with Lactobacillus rhamnosus and L. helveticus, one week after completing an antibiotic treatment, reduced the duration of diarrhea.

8. Muscles and Physical Performance

Sodium nitrate co-ingestion with protein does not augment postprandial muscle protein synthesis rates in older, type 2 diabetes patients.

In older people, dietary protein doesn’t stimulate muscle protein formation as efficiently as in young people. This has been associated with impaired delivery of protein (amino acids) to muscle cells.

Evidence suggests that dietary nitrate may help improve blood flow in muscles. However, this study in elderly people with diabetes showed that eating sodium nitrate with protein does not improve the rate of muscle protein formation.

9. Infections and Immune Health

Effect of vitamin D supplementation, directly or via breast milk for term infants, on serum 25 hydroxyvitamin D and related biochemistry, and propensity to infection: a randomised placebo-controlled trial.

This randomized controlled trial in Indian infants examined the effectiveness of supplementing with vitamin D, 10 µg/day for 9 months, combined with 15 minutes of sun exposure every day, on levels of vitamin D and the risk of infections.

The study found that vitamin D supplementation, either direct or from the mother through breast milk, was better for maintaining normal vitamin D levels than sun exposure alone. Supplementing also reduced the risk of lung infections or diarrhea.

10. Skin Health

Consumption of dairy in teenagers with and without acne.

Acne is a skin disease characterized by greasy skin, blackheads and pimples. It is most common among teenagers. Evidence suggests that high intake of certain foods, such as dairy or sugar, may increase the risk of acne in predisposed individuals.

This observational study in 225 adolescents found that total dairy intake was not associated with acne. However, intake of low-fat milk was significantly higher among those who had acne.

11. Pregnancy and Infant Health

Intakes of Micronutrients Are Associated With Early Growth in Extremely Preterm Infants.

This observational study in extremely preterm infants showed that a low folate intake was associated with poor growth, both in weight and length. High iron intake was also linked with poor length gain and head circumference.

12. Longevity and Healthy Aging

Alcohol drinking patterns and risk of functional limitations in two cohorts of older adults.

Difficulties peforming physical or mental tasks in daily life are collectively known as functional limitations.

This observational study in older people showed that moderate alcohol intake, as well as the Mediterranean Drinking Pattern, was linked to a reduced risk of functional limitations. The causality of this association is unknown.

13. Women’s Health

Serum caffeine and paraxanthine concentrations and menstrual cycle function: correlations with beverage intakes and associations with race, reproductive hormones, and anovulation in the BioCycle Study.

Health professionals sometimes advise women to limit their caffeine intake when trying to become pregnant. However, the evidence supporting this recommendation is limited.

This study found that high circulating levels of caffeine (or its metabolite paraxanthine) were associated with reduced testosterone levels and improved menstrual cycle function in healthy women.

14. Vitamins, Minerals and Other Nutrients

Ultra-long-term human salt balance studies reveal interrelations between sodium, potassium, and chloride intake and excretion.

This long-term study examined the effects of salt intake on the levels of sodium in urine. It found suggests there is a high day-to-day variability in the urine levels of sodium, even when salt and potassium intake is constant.

The researchers concluded that 24-hour urine collections, commonly used to estimate sodium intake, are very inaccurate. Multiple-day collections are needed.