Past Week in Nutrition Science (July 15th–22n

This is our weekly selection of recently published studies and reviews in nutrition. Here are some of the most interesting findings this week:

  • Eating irregularly may adversely affect your health.
  • 7-day antibiotic treatment has no major effects on metabolism.
  • Eating salmon twice a week improves your blood lipid profile.
  • Breastfeeding may protect against childhood cancer.
  • High intakes of tomato products may possibly reduce the severity of prostate cancer.

Happy Young Woman Holding Tomatoes

Research Reviews

This week we reviewed two articles: one about the effects of irregular eating habits on metabolism and another examining the effects of short-term antibiotic treatment on metabolic factors.


Review: Irregular Eating Habits Adversely Affect Metabolism.

Article: Irregular meal-pattern effects on energy expenditure, metabolism, and appetite regulation: a randomized controlled trial in healthy normal-weight women.

Summary: This was a randomized crossover trial comparing the effects of regular and irregular eating habits on calorie expenditure, blood sugar control, hormones and self-reported appetite.

The study showed that eating irregularly may increase hunger, impair blood sugar control and reduce calorie expenditure after meals.


Review: Short-Term Antibiotic Treatment Has No Major Effects on Metabolism.

Article: Effects of Gut Microbiota Manipulation by Antibiotics on Host Metabolism in Obese Humans: A Randomized Double-Blind Placebo-Controlled Trial.

Summary: This randomized controlled trial examined the effects of short-term antibiotic treatment with amoxicillin or vancomycin on metabolic factors in obese, pre-diabetic men.

The study found that vancomycin caused considerable changes in gut microbiota, whereas amoxicillin had no significant effects. However, vancomycin had no major effects on metabolism.


New Research from Around the World

Here are summaries of the most interesting or relevant studies, categorized by subject.

  1. Obesity and Weight Loss
  2. Blood Sugar Control and Diabetes
  3. Heart Health
  4. Cancer
  5. Kidney and Urinary Health

1. Obesity and Weight Loss

No evidence for metabolic adaptation in thermic effect of food by dietary protein.

Eating is associated with a temporary increase in calorie expenditure, which is known as the thermic effect of food (TEF). Protein causes a higher TEF, compared to carbs or fat.

This study showed that the effects of protein on TEF did not change following a low (5%), normal (15%) or high-protein (25%) diet for 56 days.


Bottle Size and Weight Gain in Formula-Fed Infants.

This observational study in formula-fed infants suggests that a large bottle size may increase their risk of gaining excessive weight, compared to a smaller bottle size.


Adherence to the Mediterranean dietary pattern and BMI change among US adolescents.

Previous observational studies suggest that following the Mediterranean dietary pattern (MDP) reduces the risk of weight gain and promotes weight loss.

This observational study supports previous findings. It showed that adhering to the MDP was associated with lower weight gain.


Associations between liking for fat, sweet or salt and obesity risk in French adults: a prospective cohort study.

This prospective observational study found that a high liking for fat is linked to a greater risk of obesity, whereas a high liking for sweet taste was linked to a decreased risk. In contrast, salt liking was not significantly linked to obesity.


Protein intake during pregnancy and offspring body composition at 6 years: the Generation R Study.

This observational study suggests that higher protein intakes during pregnancy are linked to greater lean mass in the children when they are 6 years old.

In contrast, protein intakes during pregnancy were not significantly associated with fat mass in the child.


2. Blood Sugar Control and Diabetes

Polyphenol- and fibre-rich dried fruits with green tea attenuate starch-derived postprandial blood glucose and insulin: a randomised, controlled, single-blind, cross-over intervention.

High amounts of fiber or polyphenol antioxidants generally improve blood sugar control after a meal. They partly work by inhibiting digestive enzymes and slowing the absorption of sugar/carbs.

This randomized controlled trial supports previous studies showing that adding fiber and polyphenols to starch significantly lowered post-meal rises in blood sugar and insulin.


Consumption of soy foods and isoflavones and risk of type 2 diabetes: a pooled analysis of three US cohorts.

Isoflavonoids, or isoflavones, are plant compounds found in legumes, especially soybeans.

This observational study found that dietary intake of isoflavones was linked to a slightly lower risk of type 2 diabetes in US men and women who generally ate low or moderate amounts of soy foods.


3. Heart Health

Association between dietary fibre intake and fruit, vegetable or whole-grain consumption and the risk of CVD: results from the PREvención con DIeta MEDiterránea (PREDIMED) trial.

This observational study indicates that eating a lot of fruits and vegetables reduces the risk of heart disease.

Conversely, fiber and fruit consumption alone were not significantly linked to heart disease risk in fully-adjusted statistical models.


Whole-grain consumption and the risk of all-cause, CVD and cancer mortality: a meta-analysis of prospective cohort studies.

This large meta-analysis of observational studies including a total of 816,599 people showed that high intakes of whole grains were associated with a reduced risk of death from heart disease and cancer.

Additionally, for each 3-serving increase in whole grains per day, there was a 19% decrease in death from all causes.


Twice weekly intake of farmed Atlantic salmon (Salmo salar) positively influences lipoprotein concentration and particle size in overweight men and women.

This randomized crossover trial showed that eating farmed salmon (90–270 grams) twice weekly for 4 weeks improved the blood lipid profile, reducing triglyceride levels and increasing HDL cholesterol levels.

Additionally, the levels of large LDL cholesterol particles increased dose dependently. Previous studies have linked similar changes with a reduced risk of heart disease.


Breast Milk Consumption in Preterm Neonates and Cardiac Shape in Adulthood.

Preterm birth is associated with changes in heart shape and function that may have adverse effects on heart health.

This observational study in preterm infants suggests that exclusive breastfeeding may improve their heart function.


Multivitamin use and the risk of hypertension in a prospective cohort study of women.

This observational study in middle-aged and older women indicates that taking multivitamins does not affect their risk of developing hypertension.


Association of alcohol consumption with coronary artery disease severity.

Coronary artery disease (CAD) is when the blood vessels that supply the heart with oxygen become clogged, increasing the risk of heart attacks.

This observational study in people with suspected CAD showed that drinking moderate amounts of alcohol is associated with a lower risk of CAD, compared to heavy drinking.


4. Cancer

The Impact of Underweight Status on the Prognosis of Ovarian Cancer Patients: A Meta-Analysis.

Being underweight or nutrient deficient is associated with worse outcomes for those who have cancer, but not all studies agree.

This meta-analysis of observational studies suggests that being underweight doesn’t negatively affect the prognosis of patients with ovarian cancer. However, the evidence is weak overall.


Breastfeeding, Other Early Life Exposures and Childhood Leukemia and Lymphoma.

This observational study indicates that breastfeeding may protect against cancer. Specifically, children who were breastfed at one point were 64% less likely to develop leukemia or lymphoma.

Additionally, there was a dose-response effect. Children who were breastfed for longer periods were at a reduced risk of leukemia and lymphoma, compared to those who were breastfed for a shorter period.


Tomato-based randomized controlled trial in prostate cancer patients: effect on PSA.

Prostate cancer is associated with elevated circulating levels of prostate-specific antigen (PSA). This 3-week trial examined the effects of eating tomato products containing 30 mg of lycopene per day on PSA levels.

The study suggests that eating tomato products decreases PSA levels in patients with non-metastatic prostate cancer. However, the effect may depend on cancer severity, as well as blood levels of lycopene, selenium and omega-3.


5. Kidney and Urinary Health

Dietary Advanced Glycation End Products and Risk of Chronic Kidney Disease.

Advanced glycation end products (AGEs) are a group of compounds that naturally form in your body when sugar reacts with protein. High blood sugar levels promote their formation, but AGEs are also found in some high-fat foods.

This observational study found that a higher dietary intake of carboxymethyl lysine — a major dietary AGE found in fat — was linked to a greater risk of chronic kidney disease.