This is an overview of interesting nutrition research published from Friday, April 15th, to Friday, April 22nd, 2016.
This week, we reviewed two articles: one on the effects of A2 milk on digestive symptoms and another examining the effects of linoleic acid on heart disease risk.
Article: Effects of milk containing only A2 beta casein versus milk containing both A1 and A2 beta casein proteins on gastrointestinal physiology, symptoms of discomfort, and cognitive behavior of people with self-reported intolerance to traditional cow’s milk.
Summary: This randomized controlled trial compared the effects of A2 milk and conventional milk on digestive symptoms, inflammation and mental performance in Chinese adults with self-reported lactose intolerance.
The study showed that while conventional milk causes adverse symptoms for those sensitive to milk, A2 milk appeared to have no adverse effects. However, further studies need to confirm these findings.
Summary: This study analyzed unpublished data from a large randomized controlled trial examining the effects of high linoleic acid intake on cholesterol levels and heart disease. The trial was conducted in the late ’60s and early ’70s.
The main findings were that replacing saturated fat with linoleic acid has no benefits for heart health. While it does lower cholesterol, it may still increase the risk of heart disease and death.
New Research From Around the World
A number 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
- Metabolic Syndrome
- Heart Health
- Appetite and Eating
- Brain and Mental Health
- Digestive Health
- Allergies and Auto-Immune Disorders
- Infections and Immune Health
- Pregnancy and Infant Health
- Longevity and Healthy Aging
1. Obesity and Weight Loss
Prebiotics are a group of fiber that can change the composition of the gut microbiota and stimulate the growth of beneficial gut bacteria. Studies indicate that supplementing with prebiotics may help prevent obesity and chronic disease.
This review discusses the role of the gut microbiota in childhood obesity, and the possible benefits of supplementing with prebiotics.
This observational study in children indicates that higher eating and snacking frequency may increase the risk of weight gain and obesity. However, meal frequency was not significantly associated with either.
2. Metabolic Syndrome
The Dietary Inflammatory Index (DII) rates the inflammatory potential of a diet. Some foods are pro-inflammatory, whereas others are anti-inflammatory or neutral.
This observational study suggests that eating foods that promote inflammation, as measured using the DII, does not increase people’s risk of metabolic disease.
3. Heart Health
This observational study linked foods that promote inflammation, as measured by the Dietary Inflammatory Index, to a higher risk of heart attack.
This randomized controlled trial in 40 adults with elevated cholesterol levels examined the health benefits of a dietary supplement containing 30 g of coenzyme Q10 and 10 g of monacolins — compounds found in red yeast rice.
The study showed that taking this supplement daily for 6 months reduced LDL-cholesterol by 26% and arterial stiffness by 5%.
This observational study suggests that dietary zinc and iron may reduce the risk of lung cancer. Conversely, dietary calcium, copper, magnesium and selenium were not significantly associated with lung cancer risk.
This observational study in Japanese women found that a Western dietary pattern was associated with an increased risk of breast cancer. In contrast, a prudent diet and a traditional Japanese diet were not linked with breast cancer risk.
This observational study in American women suggests that a vegetarian diet does not decrease the risk of breast cancer, compared to non-vegetarians. However, vegans may be at a lower risk.
5. Appetite and Eating
This study in overweight and obese individuals showed that they liked eating a low-fat, high-carb meal (LFHC) better than a high-fat, low-carb meal (HFLC). Calorie intake was higher during the LFHC meal, and fullness was higher afterward.
6. Brain and Mental Health
Lutein is an antioxidant found in high amounts in many vegetables, such as kale, spinach, turnip greens, watercress, romaine lettuce, zucchini and Brussels sprouts.
This observational study in elderly people showed that high circulating levels of lutein were linked with a reduced risk of dementia.
This observational study in children from rural Ethiopia found that low levels of iron and selenium were linked with poor mental performance.
This review discusses the evidence linking food patterns with mental depression. Studies indicate that diets characterized by lots of seafood, vegetables, fruits and nuts may potentially reduce the risk of depression.
This observational study suggests that eating foods that promote inflammation, as measured by the Dietary Inflammatory Index, may impair mental performance.
7. Digestive Health
Psyllium husk is a type of fiber made from the seed covering of psyllium plants.
This randomized controlled trial in children with irritable bowel syndrome (IBS) showed that supplementing with psyllium husk for 6 weeks reduced the number of abdominal pain episodes.
8. Allergies and Autoimmune Disorders
Kawasaki disease is a rare autoimmune condition, most often seen in Asian children under 5 years of age. It causes inflammation throughout the body, affecting blood vessels, lymph nodes and skin.
This observational study showed that the dietary exposure of soy isoflavones is associated with an increased risk of Kawasaki disease in US children.
9. Infections and Immune Health
This review discusses the potential of larch arabinogalactan for improving immune function. The authors conclude that arabinogalactan may help fight the common cold, but how this works is unknown.
10. Pregnancy and Infant Health
Long-chain, omega-3 polyunsaturated fatty acids, such as EPA and DHA, are found in fish oil. They are generally considered healthy, but some scientists are concerned they may increase oxidative stress in the body.
This randomized controlled trial in pregnant mothers showed that supplementing with omega-3 from fish oil (400 mg EPA and DHA daily) decreased markers of oxidative stress and increased levels of antioxidants in both the mother and child.
11. Longevity and Healthy Aging
Telomeres are sequences of DNA at the ends of DNA strands, protecting them from fusing with neighboring strands. They naturally shorten with age, but oxidative stress may accelerate their shortening, possibly contributing to aging.
This observational study in Chinese adults suggests that elevated blood sugar levels may speed up telomere shortening. Conversely, eating legumes, nuts, fish and seaweed may protect the telomeres.
Sarcopenia describes the loss of muscle mass that occurs with age. It’s a common cause of poor health, frailty and impaired quality of life among the elderly.
This review discusses the most important dietary considerations in the prevention of sarcopenia: adequate amounts of protein, frequency of protein consumption, sufficient protein quality and strength exercises.