New Research From Around the World
Lots of recent 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
- Brain and Mental Health
- Liver Health
- Lung Health
- Bone Health
- Low vitamin B12 intake during infancy may affect intelligence and brain function later in childhood.
- High lead levels in childhood may impair intelligence and socioeconomic status in adulthood.
- Fish oil or evening primrose oil may reduce the symptoms of arthritis.
- connection between sleep, metabolism, ageing and longevity
1. Obesity and Weight Loss
This review concluded that high-carb diets are as effective as low-carb diets at reducing body weight, blood sugar levels and LDL cholesterol levels in people with type 2 diabetes.
However, high-carb diets can raise triglyceride levels and reduce levels of beneficial HDL cholesterol, potentially increasing the risk of heart disease. However, these effects can be ameliorated by eating carbs that have a low glycemic index.
This prospective observational study in 29,152 adults showed that the intake of long-chain omega-3 fatty acids was not consistently associated with changes in body weight or waist circumference.
2. Blood Sugar Control and Diabetes
This observational study in pregnant, Asian women found that high folate levels, in combination with insufficient vitamin B12 levels, were associated with a 97% higher risk of diabetes during pregnancy (GDM).
High folate levels without vitamin B12 insufficiency were linked to higher blood sugar levels and a 29% higher risk of GDM. In contrast, high vitamin B12 levels were associated with lower blood sugar levels.
This prospective observational study in 3,349 adults found that eating a lot of legumes was associated with a reduced risk of type 2 diabetes (T2D).
Specifically, those who ate the most legumes had a 35% lower risk of developing T2D. The researchers observed a similar association when they investigated lentil consumption separately.
This observational study in 292,827 people showed that children whose body mass index was above average were more likely to develop type 2 diabetes as adults. This association was stronger among women than men.
A retrospective analysis of a societal experiment among the Danish population suggests that exposure to extra doses of vitamin A during fetal development may lower type 2 diabetes mellitus (T2DM) risk later in life.
This Danish observational study showed that adults whose mothers had eaten vitamin A-enriched margarine during pregnancy were at a lower risk of developing type 2 diabetes.
This observational study in 8,555 adults with normal blood sugar levels found that reduced magnesium levels were linked to an 18% and 12% increased risk of diabetes and prediabetes, respectively.
The authors concluded that magnesium levels may interact with genes that are associated with the risk of diabetes.
3. Heart Health
High levels of oxidized LDLs have been linked to an increased risk of heart disease. They’re also used as a marker of oxidative stress, which is associated with several chronic diseases.
This controlled study in 68 people with metabolic syndrome showed that taking 1,800 mg of artichoke leaf extract for three months reduced levels of oxidized LDLs, compared to a placebo containing cornstarch and lactose.
This observational study in 2,242 young adults with African ancestry showed that blood pressure tended to increase when vitamin D levels were low. Blood pressure was the highest when circulating vitamin D levels fell below 20 ng/ml.
This 28-day crossover study in 51 adults aged 21–73 compared the effects of eating 28–64 grams of cashew nuts or potato chips per day, while keeping the total intake of carbs, protein and fat constant between groups.
Compared to potato chips, cashew nut intake significantly improved the blood lipid profile by reducing total cholesterol, non-HDL cholesterol and the ratio of total cholesterol to HDL cholesterol.
This 12-year observational study followed 7,169 Australian women who were 52 years old when the study started.
The study showed that following a pro-inflammatory diet was associated with a greater risk of developing high blood pressure (hypertension).
This four-year controlled study in 2,303 healthy, postmenopausal women aged 55 and older showed that taking daily vitamin D (2000 IU) and calcium (1,500 mg) supplements did not lower the risk of cancer, compared to a placebo.
5. Brain and Mental Health
This observational study in Nepalese children found that low vitamin B12 levels in infancy were associated with the poor development of several cognitive functions that were measured when the children were five years old.
Effect of long-term omega 3 polyunsaturated fatty acid supplementation with or without multidomain intervention on cognitive function in elderly adults with memory complaints (MAPT): a randomised, placebo-controlled trial.
This three-year controlled study in 1,680 older French adults with memory problems investigated the effects of taking daily omega-3 supplements, which provided 800 mg of DHA and 225 mg of EPA, on cognitive function.
The study showed that long-chain omega-3 supplements had no significant effects on cognitive decline, compared to a placebo.
Lead is a heavy metal that is toxic to neurons. Consumption of lead-contaminated food leads to its accumulation in body tissues and may cause health problems.
This prospective observational study in 1,007 young people from New Zealand showed that high circulating lead levels at age 11 were linked to a lower IQ, cognitive function and socioeconomic status at age 38.
6. Liver Health
Synbiotics (SB) are supplements containing both probiotics and prebiotics. This study examined the effects of SB on the symptoms of non-alcoholic fatty liver disease (NAFLD).
The study included 50 adults with NAFLD and normal or low BMI. It found that supplementing with SB for seven months improved liver health and lowered fasting blood sugar, triglyceride levels and several inflammatory markers.
7. Lung Health
This meta-analysis concluded that a high intake of fruits and vegetables may reduce the severity of asthma. A high intake of vegetables was also associated with a lower risk of asthma.
The anti-inflammatory effects of fruits and vegetables seem to be responsible. Studies show that they may protect against lung inflammation.
8. Bone Health
This was a controlled study in 240 healthy children and adolescents aged 8–16 who consumed low amounts of dairy and less than 800 mg of calcium per day.
The study showed that eating three daily servings of dairy, providing about 900 mg of calcium, had no significant effects on bone mineral density or body composition, compared to a placebo.
Rheumatoid arthritis (RA) is a chronic autoimmune disorder that affects the joints. It’s characterized by inflamed, swollen and painful joints, most commonly in the hands.
This 12-week controlled study in 60 adults with RA showed that taking fish oil or evening primrose oil supplements significantly reduced self-assessed symptoms of RA, such as tender joints, compared to a placebo.
One of the concerns associated with a high intake of long-chain omega-3 fatty acids (LC n-3) or fish oil is their blood-thinning effect, which may increase the risk of bleeding.
However, this review of eight studies found no evidence of changes in blood coagulation values or an increased bleeding risk with the use of LC n-3, even when 1.5 grams were taken daily for a year or at short-term doses of 10 grams per day.
This observational study in 890 pregnant women from Singapore found that vitamin D deficiency was linked to a higher risk of poor sleep quality and night-time eating, compared to women who had sufficient vitamin D levels.