This is our weekly selection of recently published studies and reviews in nutrition.
Here are some of the most interesting findings this week:
Obese and lean people’s brains respond differently to sugar.
Eating too much glucose or fructose for 8 days doesn’t increase inflammation.
Vitamin D3 supplements may improve insulin sensitivity in diabetics.
Certain gut bacteria may increase the severity of rheumatoid arthritis.
Weight loss reduces the symptoms of psoriasis, with long-term benefits.
Cold exposure may promote weight loss and gut microbiota changes.
Happy Summer Woman with Veggies
Research Reviews
This week we reviewed one study about the effects of sugar on brain activity and another about how sugar affects inflammation.
Review: Obese People’s Brains Respond Differently to Sugar.
Article: Altered Brain Response to Drinking Glucose and Fructose in Obese Adolescents.
Summary: This observational study examined how glucose or fructose affects brain activity in obese and lean adolescents.
Both affected brain activity (brain blood flow) differently in obese and lean people. The authors concluded that obese teens are more likely to give in to sugar cravings.
Review: Does Excessive Sugar Intake Cause Inflammation?
Article: No differential effect of beverages sweetened with fructose, high-fructose corn syrup, or glucose on systemic or adipose tissue inflammation in normal-weight to obese adults: a randomized controlled trial.
Summary: This 8-day, randomized controlled trial tested how eating too much glucose, fructose or high-fructose corn syrup affects inflammatory markers.
The study showed that short-term, excessive sugar consumption does not affect inflammatory markers — CRP and IL-6 — in lean and obese adults.
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
Kidney and Urinary Health
Arthritis
Skin Health
Longevity and Healthy Aging
Vegetarian and Vegan Diets
Contaminants and Food Safety
Vitamins, Minerals and Other Nutrients
1. Obesity and Weight Loss
Food cravings in pregnancy: Preliminary evidence for a role in excess gestational weight gain.
Pregnant women answered the Food Craving Inventory, a questionnaire that quantifies the frequency of cravings and how often people give in to them.
The findings indicate that cravings and eating a lot of craved foods, mainly sugar and fast food, increases the risk of excessive weight gain during pregnancy.
Altered Microbiota Contributes to Reduced Diet-Induced Obesity upon Cold Exposure.
This mouse study showed that cold exposure (4 weeks at 54°F or 12°C) was associated with changes in the gut microbiota.
When bacteria-free mice on a high-fat diet were transplanted with bacteria from cold-exposed mice, they gained less weight and had better blood sugar control than mice who got bacteria from mice housed at 84°F (29°C).
2. Blood Sugar Control and Diabetes
Plant-Based Dietary Patterns and Incidence of Type 2 Diabetes in US Men and Women: Results from Three Prospective Cohort Studies.
This observational study in women from the Nurses’ Health Study indicates that plant-based diets may reduce the risk of type 2 diabetes. This especially applied to whole, unprocessed plant foods.
Vitamin D3-Supplemented Yogurt Drink Improves Insulin Resistance and Lipid Profiles in Women with Gestational Diabetes Mellitus: A Randomized Double Blinded Clinical Trial.
This was a 16-week, randomized controlled trial in women with diabetes during pregnancy. It showed that eating yogurt enriched with vitamin D3 significantly improved insulin sensitivity and blood lipid profiles, compared to plain yogurt.
3. Heart Health
Dietary Quality Indices in Relation to Cardiometabolic Risk among Finnish Children Aged 6–8 Years – the PANIC study.
This observational study examined the association of heart disease risk with the results of 4 dietary quality indices in Finnish children. Only the Finnish Children Healthy Eating Index was associated with a reduced risk of heart disease in boys.
In contrast, the Dietary Approaches to Stop Hypertension (DASH) Score, Baltic Sea Diet Score (BSDS) and the Mediterranean Diet Score (MDS) were not significantly associated with reduced heart disease risk in children.
Whole Grain Intake and Mortality From All Causes, Cardiovascular Disease, and Cancer: A Meta-Analysis of Prospective Cohort Studies.
This meta-analysis of other studies showed that eating a lot of whole-grain cereals was associated with a lower risk of death, especially from heart disease.
4. Cancer
The effects of oral glutamine on clinical and survival outcomes of non-small cell lung cancer patients treated with chemoradiotherapy.
Glutamine is an amino acid used in protein synthesis. Cells that are rapidly dividing often use glutamine as an energy source.
This study in lung cancer patients undergoing chemoradiotherapy showed that taking 10 grams of glutamine, 3 times a day for over a year, reduced the risk of weight loss and severe esophagitis. It also improved survival outcomes.
5. Appetite and Eating
Effects of Bite Count Feedback from a Wearable Device and Goal Setting on Consumption in Young Adults.
This study suggests that using an electronic device providing a bite count feedback while eating may reduce calorie intake during a single meal.
6. Brain and Mental Health
Association of Vitamin B12, Folate, and Sulfur Amino Acids With Brain Magnetic Resonance Imaging Measures in Older Adults: A Longitudinal Population-Based Study.
This observational study in people aged 60 years or older showed that higher circulating levels of vitamin B12 were linked to decreased total brain volume loss.
In contrast, higher homocysteine levels were linked to faster total brain volume loss. Randomized controlled trials need to confirm these findings.
Feeding the Brain – The effects of micronutrient interventions on cognitive performance among school-aged children: a systematic review of randomized controlled trials.
This review of randomized controlled trials concluded that micronutrient deficiencies may impair fluid intelligence — the capacity to solve problems in new situations.
Studies still need to evaluate how micronutrients affect other aspects of intelligence.
7. Digestive Health
The efficacy and safety of probiotics for prevention of chemoradiotherapy-induced diarrhea in people with abdominal and pelvic cancer: a systematic review and meta-analysis.
This review and meta-analysis evaluated the safety of probiotics for preventing diarrhea in people undergoing chemoradiotherapy for abdominal or pelvic cancer.
The reviewers concluded that probiotics may be useful for preventing or reducing chemoradiotherapy-induced diarrhea and adverse side effects are uncommon.
8. Kidney and Urinary Health
The consumption of fish cooked by different methods was related to the risk of hyperuricemia in Japanese adults: A 3-year follow-up study.
Hyperuricemia is when there are abnormally high levels of uric acid in the blood. Untreated cases may increase the risk of gout and kidney failure.
This observational study in Japanese adults showed that eating raw or roasted fish, but not boiled or fried fish, was associated with a higher risk of hyperuricemia.
9. Arthritis
Dysbiosis contributes to arthritis development via activation of autoreactive T cells in the intestine.
Previous studies have shown that the types of intestinal bacteria in your gut may influence arthritis. For example, some early rheumatic arthritis patients have a gut microbiota dominated by Prevotella copri.
In this study, transplanting fecal bacteria from arthritic humans into mice increased inflammation and arthritis severity, compared to bacteria from healthy humans.
10. Skin Health
Long-term effects of weight reduction on the severity of psoriasis in a cohort derived from a randomized trial: a prospective observational follow-up study.
Psoriasis is characterized by patches of red and scaly skin. Previous randomized controlled trials have shown that weight loss may reduce the severity of psoriasis.
This observational follow-up study suggests that long-term weight loss has sustained benefits for psoriasis.
11. Longevity and Healthy Aging
Sugary beverage and food consumption, and leukocyte telomere length maintenance in pregnant women.
Telomeres are sequences of DNA at the ends of DNA strands that protect them from fusing with neighboring strands. They naturally shorten with age, but oxidative stress may accelerate this, possibly contributing to aging.
This observational study in overweight and obese pregnant women showed that drinking less sugar-sweetened beverages was associated with increased telomere length in white blood cells. This didn’t apply to other sugary foods.
Effect of Calorie Restriction on Mood, Quality of Life, Sleep, and Sexual Function in Healthy Nonobese Adults.
Calorie restriction increases longevity in many animals and reduces disease risk. This 2-year, randomized controlled trial tested the health effects of 25% restriction.
Compared to the control, calorie restriction led to greater weight loss and improved general health. It also reduced tension and improved relationships, sexual drive and sleep. It had no negative effects on health-related quality of life.
12. Vegetarian and Vegan Diets
Amino acid changes during transition to a vegan diet supplemented with fish in healthy humans.
Obese people and diabetics tend to have high levels of branched-chain amino acids (BCAAs), aromatic amino acids and sulfur amino acids.
This study showed that going on a vegan diet, supplemented with fish, lowered circulating levels of BCAAs. These findings suggest that high levels of BCAAs result from a diet high in meat, poultry, eggs and dairy products.
13. Contaminants and Food Safety
Association of Rice and Rice-Product Consumption With Arsenic Exposure Early in Life.
Rice is commonly eaten by infants and is a major ingredient in many infant foods. It may also contain high levels of inorganic arsenic. Chronic, high intake of arsenic has been associated with many health problems.
This observational study showed that arsenic levels were higher in the urine of children who ate infant rice cereal. Arsenic levels in rice snacks ranged from 36 to 568 ng/g of organic arsenic and 5–201 ng/g of inorganic arsenic.
14. Vitamins, Minerals and Other Nutrients
Mangiferin: A xanthonoid with multipotent anti-inflammatory potential.
Mangiferin is a yellow polyphenol antioxidant found in mangoes. This review discussed the potential health benefits of maniferin.
Like other polyphenols, it might help reduce the risk of chronic diseases through its antioxidant and anti-inflammatory effects. However, human studies are lacking.
Short-term ubiquinol supplementation reduces oxidative stress associated with strenuous exercise in healthy adults: A randomized trial.
Coenzyme Q10 exists in three forms, one of which is called ubiquinol. In the body, ubiquinol plays a role in energy production and antioxidant defenses. Dietary sources include liver, meat, fish, parsley and broccoli.
This randomized controlled trial in healthy, well-trained people showed that taking 200 mg of ubiquinol before exercise, every day for 2 weeks, decreased oxidative stress and increased circulating levels of nitric oxide.
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