Find the most important recent research around specific foods and cardiovascular health.
Stacey Lockyer, Anne E de la Hunty, Simon Steenson, Ayela Spiro, Sara A Stanner. Walnut consumption and health outcomes with public health relevance—a systematic review of cohort studies and randomized controlled trials published from 2017 to present. Nutrition Reviews, 2022;, nuac040, https://doi.org/10.1093/nutrit/nuac040
A systematic review has been published that analysed studies investigating associations between walnut consumption and outcomes with public health relevance. The review identified consistent evidence from randomised controlled trials that walnut consumption improves blood lipid profiles. These results were in line with associations between walnut consumption and reduced heart disease risk found in long-term observational studies.
A new review found that consuming alpha-linolenic acid (ALA), the omega-3 found in plant-based foods like walnuts and flaxseeds, was associated with a 10% lower risk of cardiovascular disease and a 20% reduced risk of fatal coronary heart disease. In t review, investigators analysed data from previous studies to evaluate the effects of ALA on heart disease and heart disease risk factors like blood pressure and inflammation. While some of the observational studies relied on the participants reporting how often they ate certain foods to determine how much ALA they were consuming, others used biomarkers — a way of measuring levels of ALA in the blood — as a more accurate measure. After analysing the studies, the researchers found that ALA had beneficial effects on reducing atherogenic lipids and lipoproteins — for example, total cholesterol, low density-lipoprotein cholesterol and triglycerides — as well as blood pressure and inflammation.
Researchers from the Harvard T.H. Chan School of Public Health used machine learning, a subset of artificial intelligence, to identify more precisely the components in walnuts that may be responsible for potentially reducing the risk of type 2 diabetes (T2D) and cardiovascular diseases (CVD). The discovery population included 1833 participants at high cardiovascular risk from the PREvención con DIeta MEDiterránea (PREDIMED) study with available metabolomics data at baseline. A total of 19 metabolites were significantly associated with walnut consumption, and this metabolite profile was inversely associated with T2D incidence and CVD incidence.
This observational study found that regular consumption of foods rich in omega-3s, including walnuts and fish, can reduce risk of death three years after suffering a heart attack. Additionally, the consumption of both ALA and EPA provided the greatest benefit, suggesting a synergistic effect and unique protective qualities when both types of omega-3 are consumed.
This study examined associations between tree nut snack consumption and diet quality, and CVD risk markers, in a nationally representative UK adult population, using data from the UK National Diet and Nutrition Survey (NDNS) rolling programme 2008–2014. Participants consuming tree nuts as a snack reported better diet quality and were associated with lower CVD risk factors. They had a higher Mediterranean Diet Score and modified Healthy Diet Score relative to non-consumers, as well as lower body mass index, waist circumference, and systolic and diastolic blood pressure. In addition, those consuming tree nuts had higher intakes of n-3 and n-6 polyunsaturated fatty acids, fibre, vitamins A, C and E, as well as B vitamins, potassium, and some minerals (magnesium, selenium and iron), and lower intakes of saturated and trans fatty acids, free sugars and sodium. The findings suggest that replacing less healthy snacks with tree nuts should be encouraged and can have a number of positive effects.
Xiaoran Liu, Marta Guasch‐Ferré, Jean‐Philippe Drouin‐Chartier, et al (2020) Changes in Nut Consumption and Subsequent Cardiovascular Disease Risk Among US Men and Women: 3 Large Prospective Cohort Studies. J Am Heart Assoc 2020; 9: e013877.
https://doi.org/10.1161/JAHA.119.013877
This recent study asked over 190,000 men and women in the US to record their nut consumption over a four-year period. The participants’ risk for CVD was then assessed over the subsequent four years. Compared with those who consumed no nuts, the study participants who ate just half a serving a day of nuts, such as walnuts, had a lower risk of CVD, coronary heart disease and stroke.
This systematic review and meta-analysis revealed a beneficial role of nut consumption in reducing the incidence of, and mortality from, different CVD outcomes.
Results from this trial found changes in specific gut bacteria in individuals at increased cardiovascular risk following diets that replaced saturated fats with walnuts compared to a placebo. Gordonibacter enrichment and the inverse association between Lachnospiraceae and cardiovascular risk factors following the walnut diet suggest that the gut microbiota may contribute to the health benefits of walnut consumption in adults at cardiovascular risk.
Data from three prospective, longitudinal cohorts among health professionals in the US found that increasing daily consumption of nuts was
associated with less long-term weight gain and a lower risk of obesity in adults. The authors suggested that replacing 0.5 servings/day of less healthful foods with nuts may be a simple strategy to help prevent gradual long-term weight gain and obesity.
Meat
In this cohort study of 29 682 US adults pooled from 6 prospective cohort studies, intake of processed meat, unprocessed red meat, or poultry was significantly associated with incident cardiovascular disease, but fish intake was not. Intake of processed meat or unprocessed red meat was significantly associated with all-cause mortality, but intake of poultry or fish was not.
This updated meta-analysis of randomized controlled trials on red meat and cardiovascular risk factors concluded that inconsistencies regarding the effects of red meat on cardiovascular disease risk factors are attributable, in part, to the composition of the comparison diet. Substituting red meat with high-quality plant protein sources, but not with fish or low-quality carbohydrates, leads to more favourable changes in blood lipids and lipoproteins.
Timothy J. Key, Paul N. Appleby, et al (2019) Consumption of Meat, Fish, Dairy Products, and Eggs and Risk of Ischemic Heart Disease. A Prospective Study of 7198 Incident Cases Among 409 885 Participants in the Pan-European EPIC Cohort. Circulation.139:2835–2845
Meat, fish, dairy products, and eggs and risk for IHD were examined in the pan-European EPIC cohort (European Prospective Investigation Into Cancer and Nutrition). In this cohort, risk for IHD was positively associated with consumption of red and processed meat.
Dairy
Data from the European Prospective Investigation into Cancer and Nutrition–Norfolk (EPIC-Norfolk) study found that different dairy subtypes may differently influence cardiometabolic risk through adiposity and lipid pathways. For lipids, an increase in milk (total and low-fat) or yogurt consumption was positively associated with HDL cholesterol. An increase in total low fat dairy was negatively associated with LDL cholesterol whereas high-fat dairy (total, butter, and high-fat cheese) consumption was positively associated.
Data from 3 large cohorts do not support an inverse association between high amount of total dairy consumption and risk of mortality. The health effects of dairy could depend on the comparison foods used to replace dairy. In food substitution analyses, consumption of nuts, legumes, or whole grains instead of dairy foods was associated with a lower mortality, whereas consumption of red and processed meat instead of dairy foods was associated with higher mortality.
Eggs
Andrew O Odegaard (2020) Egg consumption and cardiovascular disease BMJ;368:m744
An Editorial examining the evidence for egg consumption and cardiovascular health.
Soya
A higher intake of isoflavones and tofu was associated with a lower risk of coronary heart disease in 3 large prospective cohorts of US men and women. The inverse association of tofu was primarily observed among younger women before the menopause or postmenopausal women who did not use hormone replacement therapy.