Prevent memory loss with a powerful nutrient in cucumbers
Salk Institute for Biological Studies, February 16, 2021
The results of a recent study are offering new hope that avoiding memory loss related to aging as well as Alzheimer’s disease could be as simple as eating more cucumbers.
Many older adults resign themselves to memory loss as part of the aging process. However, a study out of the the Salk Institute for Biological Studies has shown that this doesn’t have to be the case. The health benefits of cucumbers are many, and one of them seems to be better memory and even the prevention of Alzheimer’s disease.
Researchers working with mice that normally developed the symptoms of Alzheimer’s (including memory loss) discovered that a daily dose of a flavonol called fisetin prevented these and other related impairments. This improvement occurred despite the continued formation of amyloid plaques, the brain proteins commonly blamed for Alzheimer’s.
A natural food cure for memory loss
The compound fisetin is found in numerous vegetables and fruits but is especially concentrated in strawberries and cucumbers. This flavonol is quite effective in stopping memory loss in mice and holds hope for humans as well.
In the past, the main approach to treating Alzheimer’s symptoms was to target amyloid plaques in the brain. The findings of this study call into question the assumption that these proteins are largely responsible for the effects of Alzheimer’s.
Even in animals with no signs of Alzheimer’s and otherwise normal functioning, fisetin has been shown to improve memory. However, its ability to prevent memory loss associated with Alzheimer’s disease could have profound implications for humans.
Cucumbers protect the brain from inflammation
Fisetin works by switching on a cellular pathway associated with the process of retrieving memories in the brain. Over a decade ago, other researchers discovered the compound fisetin assists in protecting the neurons of the brain from agingand its associated effects. It was found that this potent compound has both anti-inflammatory and antioxidant effects on brain cells.
The list of health benefits of cucumbers, strawberries and other fruits and vegetables containing fisetin now include brain and memory improvements. By extension, fisetin has properties that can be highly beneficial for those at risk for Alzheimer’s.
Other health benefits of cucumbers
In addition to improving memory and potentially protecting against Alzheimer’s, the cucumber fruit has a range of additional nutritional and health benefits. They are low in calories (a cup of cucumbers contains just 16 calories) and assist in hydration (they are comprised of 95 percent water). They also provide flavonoids, triterpenes and lignans which offer anti-inflammatory, antioxidant and cancer-preventing benefits.
The peel and seeds in cucumbers contain beta-carotene for eye health and are the most nutrient-dense portions of the fruit. Cucumber seeds contain calcium and the skin and seeds are also excellent sources of fiber. Other vitamins include potassium, vitamin C, magnesium and manganese.
Testosterone levels increased significantly after DHEA administration among older women
Jiangxi University of Traditional Chinese Medicine, February 14, 2021
According to news originating from Jiangxi, People’s Republic of China, research stated, “Despite the fact that numerous clinical studies have evaluated the positive effects of dehydroepiandrosterone (DHEA) supplementation on testosterone concentrations and on the body mass index (BMI), more evidence is needed to certify that DHEA is a BMI-reducing agent in the elderly. This meta-analysis aims to clarify the various incompatible results and investigate the impact of DHEA supplementation on serum testosterone levels and lean body mass in elderly women.”
Our news journalists obtained a quote from the research from the Jiangxi University of Traditional Chinese Medicine, “Four scientific databases (EMBASE, PubMed/MEDLINE, Scopus and Web of Science) were searched from inception until 20 August 2020 for trials comparing DHEA with placebo. Results were presented as weighted mean differences (WMDs) and 95 % confidence intervals (CIs) based on the random effects model (DerSimonian-Laird approach). Nine arms with 793 subjects reported testosterone as an outcome measure. The overall results demonstrated that testosterone levels increased significantly after DHEA administration in elderly women (WMD: 17.52 ng/dL, 95 % CI: 6.61, 28.43, P = 0.002). In addition, DHEA administration significantly decreased the BMI (WMD:-0.39 kg/m(2), I-2 = 0.0 %).”
According to the news editors, the research concluded: “The results of the current meta-analysis support the use of DHEA supplementation for increasing testosterone concentrations in elderly women.”
This research has been peer-reviewed.
How healthy lifestyle behaviours can improve cholesterol profiles
Harvard School of Public Health, February 15, 2021
Combining healthy lifestyle interventions reduces heart disease through beneficial effects on different lipoproteins and associated cholesterols, according to a study published February 9 in eLife.
Having a healthy lifestyle has long been associated with a lower risk of developing heart disease. The new study provides more detailed information on how healthy lifestyles improve cholesterol, and suggests that combining cholesterol-lowering medications and lifestyle interventions may yield the greatest benefits to heart health.
Cholesterol-lowering medications such as statins help reduce heart risks by lowering levels of low-density lipoprotein (LDL) cholesterol, the so-called "bad" cholesterol. Healthy lifestyle interventions, including exercising regularly, having a healthy diet, lowering alcohol consumption and maintaining a healthy weight, have also been shown to lower LDL as well as increase "healthy" high-density lipoprotein (HDL) cholesterol.
"Until now, no studies have compared the lipid-lowering effects of cholesterol-lowering medications and healthy lifestyle interventions side by side," says lead author Jiahui Si, Postdoctoral Research Fellow in the Department of Epidemiology at Harvard T.H. Chan School of Public Health, Boston, Massachusetts, US.
To address this gap, Si and colleagues used a technique called targeted nuclear magnetic resonance spectroscopy to measure 61 different lipid markers in blood samples from 4,681 participants in the China Kadoorie Biobank, including cases of stroke, coronary heart disease and healthy individuals. They studied lipid markers in the blood of participants who had multiple healthy lifestyle habits and compared them to those of participants with less healthy habits. They found 50 lipid markers associated with a healthy lifestyle.
When the team looked at a subset of 927 individuals who had coronary heart disease in the next 10 years and 1,513 healthy individuals, they found 35 lipid markers that showed statistically significant mediation effects in the pathway from healthy lifestyles to the reduction of heart disease. Together, the combined beneficial effects of the lipid changes associated with healthy lifestyle practices were linked to a 14% reduced risk of heart disease. Specifically, very-low-density lipoprotein (VLDL) and HDL levels in the blood were linked to the heart-protecting benefits of healthy lifestyles.
"Using a genetic scoring technique, we could compare the effect of cholesterol-lowering drugs with that of lifestyle side by side in the study participants," says co-senior author Liming Liang, Associate Professor of Statistical Genetics in the Department of Epidemiology at Harvard T.H. Chan School of Public Health. "Our analysis confirmed that cholesterol-lowering drugs would have the expected effect in lowering LDL cholesterol, but this is much weaker compared to the effect of healthy behaviours on VLDL cholesterol which also increases the risk of heart disease."
Overall, they found that taking cholesterol-lowering medications and engaging in multiple healthy lifestyles would likely help individuals to achieve the greatest heart-protecting benefits because of the complementary effects of the drugs and healthy behaviours.
"Lifestyle interventions and lipid-lowering medications may affect different components of the lipid profile, suggesting they are not redundant strategies but could be combined for improved benefits," concludes co-senior author Jun Lv, Professor at the Department of Epidemiology & Biostatistics at the School of Public Health, Peking University Health Science Center, Beijing, China.
Role of Diet in Colorectal Cancer Incidence
Umbrella Review of Meta-analyses of Prospective Observational Studies
University of Utah, February 16
Question How credible is the evidence behind the association of dietary factors with colorectal cancer (CRC) risk in published meta-analyses of prospective observational studies?
Findings This umbrella review of 45 meta-analyses describing 109 associations found convincing evidence for an association between lower CRC risk and higher intakes of dietary fiber, dietary calcium, and yogurt and lower intakes of alcohol and red meat.
Meaning This study suggests that dietary factors may have a role in the development and prevention of CRC, but more research is needed on specific foods for which the evidence remains suggestive.
Abstract
Importance Several meta-analyses have summarized evidence for the association between dietary factors and the incidence of colorectal cancer (CRC). However, to date, there has been little synthesis of the strength, precision, and quality of this evidence in aggregate.
Objective To grade the evidence from published meta-analyses of prospective observational studies that assessed the association of dietary patterns, specific foods, food groups, beverages (including alcohol), macronutrients, and micronutrients with the incidence of CRC.
Data Sources MEDLINE, Embase, and the Cochrane Library were searched from database inception to September 2019.
Evidence Review Only meta-analyses of prospective observational studies with a cohort study design were eligible. Evidence of association was graded according to established criteria as follows: convincing, highly suggestive, suggestive, weak, or not significant.
Results From 9954 publications, 222 full-text articles (2.2%) were evaluated for eligibility, and 45 meta-analyses (20.3%) that described 109 associations between dietary factors and CRC incidence were selected. Overall, 35 of the 109 associations (32.1%) were nominally statistically significant using random-effects meta-analysis models; 17 associations (15.6%) demonstrated large heterogeneity between studies (I2 > 50%), whereas small-study effects were found for 11 associations (10.1%). Excess significance bias was not detected for any association between diet and CRC. The primary analysis identified 5 (4.6%) convincing, 2 (1.8%) highly suggestive, 10 (9.2%) suggestive, and 18 (16.5%) weak associations between diet and CRC, while there was no evidence for 74 (67.9%) associations. There was convincing evidence of an association of intake of red meat (high vs low) and alcohol (≥4 drinks/d vs 0 or occasional drinks) with the incidence of CRC and an inverse association of higher vs lower intakes of dietary fiber, calcium, and yogurt with CRC risk. The evidence for convincing associations remained robust following sensitivity analyses.
Conclusions and Relevance This umbrella review found convincing evidence of an association between lower CRC risk and higher intakes of dietary fiber, dietary calcium, and yogurt and lower intakes of alcohol and red meat. More research is needed on specific foods for which evidence remains suggestive, including other dairy products, whole grains, processed meat, and specific dietary patterns.
Pizza, burgers and the like: A single high-fat meal can damage metabolism
Deutsches Diabetes-Zentrum (Germany), February 16, 2021
The global proliferation of overweight and obese people and people with type 2 diabetes is often associated with the consumption of saturated fats. Scientists at the German Diabetes Center (Deutsches Diabetes-Zentrum, DDZ) and the Helmholtz Center in Munich (HMGU) have found that even the one-off consumption of a greater amount of palm oil reduces the body's sensitivity to insulin and causes increased fat deposits as well as changes in the energy metabolism of the liver. The results of the study provide information on the earliest changes in the metabolism of the liver that in the long term lead to fatty liver disease in overweight persons as well as in those with type 2 diabetes.
In the current issue of the "Journal of Clinical Investigation", DZD researchers working at the German Diabetes Center, in conjunction with the Helmholtz Center in Munich and colleagues from Portugal, published a scientific investigation conducted on healthy, slim men, who were given at random a flavored palm oil drink or a glass of clear water in a control experiment. The palm oil drink contained a similar amount of saturated fat as two cheeseburgers with bacon and a large portion of French fries or two salami pizzas. The scientists showed that this single high-fat meal sufficed to reduce the insulin action, e.g. cause insulin resistance and increase the fat content of the liver. In addition, changes in the energy balance of the liver were proven. The observed metabolic changes were similar to changes observed in persons with type 2diabetes or non-alcoholic fatty liver disease (NAFLD). NAFLD is the most common liver disease in the industrial nations and associated with obesity, the so-called "metabolic syndrome," and is associated with an increased risk in developing type 2 diabetes. Furthermore, NAFLD in advanced stages can result in severe liver damage.
"The surprise was that a single dosage of palm oil has such a rapid and direct impact on the liver of a healthy person and that the amount of fat administered already triggered insulin resistance", explained Prof. Dr. Michael Roden, scientist, Managing Director and Chairman at the DDZ and the German Center for Diabetes Research (Deutsches Zentrum für Diabetesforschung, DZD). "A special feature of our study is that we monitored the liver metabolism of people with a predominantly non-invasive technology, e.g. by magnetic resonance spectroscopy. This allows us to track the storage of sugar and fat as well as the energy metabolism of the mitochondria (power plants of the cell)." Thanks to the new methods of investigation, the scientists were able to verify that the intake of palm oil affects the metabolic activity of muscles, liver and fatty tissue. The induced insulin resistance leads to an increased new formation of sugar in the liver with a concomitant decreased sugar absorption in the skeletal muscles - a mechanism that makes the glucose level rise in persons afflicted with type 2 diabetes and its pre-stages. In addition, the insulin resistance of the fatty tissue causes an increased release of fats into the blood stream, which in turn continues to foster the insulin resistance. The increased availability of fat leads to an increased workload for the mitochondria, which can in the long term overtax these cellular power plants and contribute to the emergence of a liver disease.
The team of Prof. Roden suspects that healthy people, depending on genetic predisposition, can easily manage this direct impact of fatty food on the metabolism. The long-term consequences for regular eaters of such high-fat meals can be far more problematic, however.
