Advances in Nutrition May and July 2020 issues
Great reading during isolation!
Short notes
July-Eat plenty of vegetables for LPC-An insufficient pool of circulating LPC containing long-chain fatty acids could potentially limit their supply to the brain; Tea flavonoids have been suggested to offer potential benefits to cardiovascular health; There is emerging evidence indicating the beneficial effects of oleic acid (in olive oil) in regulating body weight; There is emerging evidence that an unhealthy (Western) dietary pattern may increase the risk of developing depression or anxiety, whereas a healthy (Mediterranean) dietary pattern may decrease it; Synbiotic therapy (eating fermented dairy foods and probiotics) are promising tools for the prevention and management of cardiometabolic diseases and respiratory infections; Manipulating protein intake via dietary protein or free amino acid–based supplementation diminishes muscle atrophy and/or preserves muscle function after musculo-skeletal injury; The prevalence of chronic kidney disease is increasing and eating enough potassium may prevent this.
May-Studies looking at early mortality, body weight, and glucose tolerance and diabetes show that the right mix of whole-grain foods and avoiding all refined-grain foods contributes to health; Mean intakes of calcium (in women), potassium, and vitamins A, C, and D are below recommendations and sodium intakes are well above; Full-fat dairy foods (milk, yogurt, and cheese) appear as safe as low-fat; higher protein intakes above the RDA are proposed to attenuate the loss or increase the gain of whole-body lean mass; Deficiencies in vitamins D and B-12 are associated with harmful reduced heart rate variability; One of the mechanisms in which diet can reduce the risk of disease is with regard to its impact on telomeres. Telomere length (TL) is highly correlated to chronological age and metabolic status; The Mediterranean-style dietary pattern has been highlighted as a promising candidate for reducing depressive symptoms. This review has found both an association between polyphenol consumption and depression risk, as well as evidence suggesting polyphenols can effectively alleviate depressive symptoms [as does SAMe][Mito-C is rich in polyphenols]; The average American consumes 10 times more sugar than 100 y ago; Dietary β-cryptoxanthin intake and circulating concentrations of α-carotene, β-carotene, lutein and zeaxanthin [in AREDs2] were inversely associated with bladder cancer risk; The gut-brain axis is a bilateral communication network between the gastrointestinal tract and the central nervous system, and depends on the essential amino acid tryptophan (in chicken.eggs.cheese.fish.peanuts) and contributes to the normal growth and health; Alcohol consumption during pregnancy decreases the maternal DHA status and reduces the placental transfer of DHA to the fetus.
Long notes
Recent studies show that PUFAs such as DHA (22:6) are transported across the blood–brain barrier (BBB) in the form of lysophosphatidylcholine. It accounts for 4.6% of phospholipids found in coconut oil, which make up 0.2% of lipids in coconut oil. This is compared to vegetable oils, which may contain 2-3% phospholipids.
Higher dietary PUFA intake is associated with decreased risk of cognitive decline and dementia in observational studies; however, PUFA supplementation, with fatty acids esterified in triacylglycerols did not prevent cognitive decline in clinical trials. Recent studies show that LPC is the preferred carrier of PUFAs across the BBB into the brain. An insufficient pool of circulating LPC containing long-chain fatty acids could potentially limit the supply of long-chain fatty acids to the brain, including PUFAs such as DHA, and play a role in the pathobiology of AD.
Tea flavonoids have been suggested to offer potential benefits to cardiovascular health. This review synthesized the evidence on the relation between tea consumption and risks of cardiovascular disease (CVD) and all-cause mortality among generally healthy adults. Daily tea intake as part of a healthy habitual dietary pattern may be associated with lower risks of CVD and all-cause mortality among adults. In summary, fermented milk consumption is associated with reduced cardiovascular risk, while yogurt intake is associated with a reduced risk of T2D and metabolic syndrome development in the general population. Furthermore, probiotic supplementation added into dairy matrices could be considered beneficial for lowering lipid concentrations.
A number of studies have found that oleic acid (OA), the most common MUFA in daily nutrition, has protective effects against human disease. Importantly, there is emerging evidence indicating the beneficial effects of OA in regulating body weight. Current findings lend support to advice not restricting consumption of OA-rich meals so as to maintain a healthy body weight. Oleic acid can be found naturally in numerous food sources, including edible oils, meat (such as beef, chicken, and pork), cheese, nuts, sunflower seeds, eggs, pasta, milk, olives, and avocados.
There is emerging evidence that an unhealthy dietary pattern may increase the risk of developing depression or anxiety, whereas a healthy dietary pattern may decrease it. A parallel and fast-growing body of research shows that the gut microbiota is linked with the brain in a bidirectional relation, commonly termed the microbiome–gut–brain axis. Preclinical evidence suggests that this axis plays a key role in the regulation of brain function and behavior.
Synbiotic therapy is a combination of probiotics and prebiotics. Probiotic, prebiotic and synbiotic treatment has been shown to be a promising therapy to maintain and repair the gut microbiota and gut environment. Dysbiosis of the human gut microbiome has been linked to various health conditions, including respiratory tract infections (RTIs) through the gut–lung axis. Several trials have reported that synbiotic therapy could help prevent RTIs or relieve symptoms of some diseases. This meta-analysis of clinical trials involving >10,000 individuals showed that synbiotic interventions could be an alternative nutrition strategy for conferring human health and preventing RTIs. Fermented dairy foods (FDFs) and probiotics are promising tools for the prevention and management of cardiometabolic diseases (CMDs), respectively.
Muscle atrophy and weakness occur as a consequence of disuse after musculoskeletal injury (MSI). The slow recovery and persistence of these deficits even after physical rehabilitation efforts indicate that interventions designed to attenuate muscle atrophy and protect muscle function are necessary to accelerate and optimize recovery from MSI. Evidence suggests that manipulating protein intake via dietary protein or free amino acid–based supplementation diminishes muscle atrophy and/or preserves muscle function in experimental models of disuse (i.e., immobilization and bed rest in healthy populations).
The prevalence of chronic kidney disease (CKD) is increasing and dietary interventions may be a strategy to reduce this burden. In the general population, higher potassium intake is considered protective for cardiovascular health. Due to the risk of hyperkalemia in CKD, limiting potassium intake is often recommended. However, given that poor cardiovascular function can cause kidney damage, following a low-potassium diet may be deleterious for patients with CKD
Improving awareness and accessibility of healthy diets are key challenges for health professionals and policymakers alike. While the US government has been assessing and encouraging nutritious diets via the Dietary Guidelines for Americans (DGA) since 1980, the long-term sustainability, and thus availability, of those diets has received less attention. Our results challenge prior findings that diets adhering to national dietary guidelines are more sustainable than current average diets and indicate that the Healthy US-style dietary pattern recommended by the DGA may lead to similar or increased greenhouse gas emissions, energy use, and water use compared with the current US diet. However, consistent with previous research, studies meeting inclusion criteria generally support the conclusion that, among healthy dietary patterns, those higher in plant-based foods and lower in animal-based foods would be beneficial for environmental sustainability.
It is hard to believe that Advances in Nutrition has reached its 10-year anniversary! I remember when John Suttie, the inaugural editor, circulated among the Research Interest Sections groups to explain why he was working with ASN to launch a new online review journal, and to encourage submission of review articles.
Recommended dietary patterns such as the Mediterranean diet demonstrate that the right mix of whole-grain foods and avoiding all refined-grain foods contributes to positive health outcomes. Research-based dietary guidelines suggest that consumers “make half their grains whole.” Yet some advocate ingesting only whole-grain foods (WGFs) and avoiding all refined-grain foods (RGFs). Some even recommend avoiding all grain-based foods (GBFs). This article will provide arguments to counter negative deductions about GBFs and RGFs, especially staple ones, and to support dietary guidance recommending a balance of GBFs—achieved through the right mix, type, and quantity of WGFs and RGFs. Studies looking at early mortality, body weight, and glucose tolerance and diabetes will be used as examples to characterize the literature about GBFs.
When considering the micronutrients from diet alone, mean intakes of calcium (in women), potassium, and vitamins A, C, and D are below recommendations and sodium intakes are well above. Careful beverage choices could close these gaps and be considered a part of a healthy dietary pattern.
Emerging evidence shows that the consumption of full-fat dairy foods has a neutral or inverse association with adverse cardiometabolic health outcomes, including atherosclerotic cardiovascular disease, type 2 diabetes, and associated risk factors. Thus, although low-fat dairy is a practical, practice-based recommendation, its superiority compared with full-fat dairy is not obviously supported by results from recent prospective cohort studies or intervention trials. Full-fat dairy foods (milk, yogurt, and cheese) appear as safe as low-fat.
Under stressful conditions such as energy restriction (ER) and physical activity, the RDA for protein of 0.8 g · kg−1 · d−1 may no longer be an appropriate recommendation. Under catabolic or anabolic conditions, higher protein intakes are proposed to attenuate the loss or increase the gain of whole-body lean mass, respectively.
There is accumulating evidence suggesting deficiencies in vitamins D and B-12 are associated with reduced Heart rate variability, and zinc supplementation during pregnancy can have positive effects on HRV in offspring up until the age of 5 y.
Diet, physical activity, and other lifestyle factors have been implicated in the pathophysiology of several chronic diseases, but also in a lower total mortality and longer life expectancy. One of the mechanisms in which diet can reduce the risk of disease is with regard to its impact on telomeres. Telomere length (TL) is highly correlated to chronological age and metabolic status. Individuals with shorter telomeres are at higher risk of chronic diseases and mortality. Diet may influence TL by several mechanisms such as regulating oxidative stress and inflammation or modulating epigenetic reactions. The available evidence suggests that some antioxidant nutrients, the consumption of fruits and vegetables, and Mediterranean diet are mainly associated with longer telomeres.
Depression is a mood disorder which currently affects 350 million individuals worldwide. Recently, research has suggested a protective role of diet for depression. The Mediterranean-style dietary pattern has been highlighted in several systematic reviews as a promising candidate for reducing depressive symptoms. This review has found both an association between polyphenol consumption and depression risk, as well as evidence suggesting polyphenols can effectively alleviate depressive symptoms.
The average American consuming 10 times more sugar than 100 y ago. We suggest novel approaches to assess the consequences of these changes on host–microbe interactions to determine the safety of novel sugars and sweeteners.
Dietary β-cryptoxanthin intake and circulating concentrations of α-carotene, β-carotene, and lutein and zeaxanthin were inversely associated with bladder cancer risk, a reduction of about 50%.
The gut-brain axis (GBA) is a bilateral communication network between the gastrointestinal (GI) tract and the central nervous system. The essential amino acid tryptophan contributes to the normal growth and health of both animals and humans and, importantly, exerts modulatory functions at multiple levels of the GBA. Tryptophan is the sole precursor of serotonin, which is a key monoamine neurotransmitter participating in the modulation of central neurotransmission and enteric physiological function. In addition, tryptophan can be metabolized into kynurenine, tryptamine, and indole, thereby modulating neuroendocrine and intestinal immune responses.
Alcohol consumption during pregnancy decreases the maternal DHA status and reduces the placental transfer of DHA to the fetus, resulting in less DHA being available for brain development.