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.
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.
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.
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.
- Obesity and Weight Loss
- Blood Sugar Control and Diabetes
- Heart Health
- Kidney and Urinary Health
1. Obesity and Weight Loss
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.
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.
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.
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.
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
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.
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
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.
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.
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.
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.
This observational study in middle-aged and older women indicates that taking multivitamins does not affect their risk of developing hypertension.
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.
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.
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.
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
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.