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Eating nuts twice a week link to 17% lower CVD risk

Eating nuts at least twice a week is associated with a 17% lower risk of death from cardiovascular disease, according to research presented at ESC Congress 2019 together with the World Congress of Cardiology. "Nuts are a good source of unsaturated fat and contain little saturated fat," said study author Dr Noushin Mohammadifard of Isfahan Cardiovascular Research Institute, Iran. "They also have protein, minerals, vitamins, fibre, phytosterols, and polyphenols which benefit heart health. European and US studies have related nuts with cardiovascular protection but there is limited evidence from the Eastern Mediterranean Region."

This study examined the association between nut consumption and the risk of cardiovascular disease and death in the Iranian population. A total of 5,432 adults aged 35 and older with no history of cardiovascular disease were randomly selected from urban and rural areas of the Isfahan, Arak and Najafabad counties. Intake of nuts including walnuts, almonds, pistachios, hazelnuts, and seeds was assessed in 2001 with a validated food frequency questionnaire.

Participants or family members were interviewed every two years until 2013 for the occurrence of cardiovascular events and death. The specific outcomes investigated were coronary heart disease, stroke, total cardiovascular disease, death from any cause, and death from cardiovascular disease.

During a median 12-year follow-up, there were 751 cardiovascular events (594 coronary heart disease and 157 stroke), 179 cardiovascular deaths, and 458 all-cause deaths. Eating nuts two or more times per week was associated with a 17% lower risk of cardiovascular mortality compared to consuming nuts once every two weeks. The connection was robust even after adjusting for factors that could influence the relationship such as age, sex, education, smoking, and physical activity. Nut intake was inversely associated with the other outcomes but lost significance after adjustment.

ESC guidelines list 30 grams of unsalted nuts per day as one of the characteristics of a healthy diet, while noting that the energy density of nuts is high.

"Raw fresh nuts are the healthiest," added Mohammadifard. "Nuts should be fresh because unsaturated fats can become oxidised in stale nuts, making them harmful. You can tell if nuts are rancid by their paint-like smell and bitter or sour taste."

Background: Nuts are one of the richest sources of unsaturated fatty acids, plant proteins, antioxidant vitamins, minerals and plant sterols, which have cardioprotective effects. Evidences in this context mainly came from Mediterranean and Western populations, and there is no prospective observational report from Middle East region.
Purpose: We aimed to investigate the association of nut consumption with the risk of coronary heart disease (CHD), stroke, total cardiovascular disease (CVD), all-cause death and CVD mortality among Iranian population during 2001-2013.
Methods: This population-based prospective cohort study was conducted among 5432 randomly selected participants without history of CVD aged =35 years in urban and rural areas of three counties in central Iran. The subjects were followed for 13 years from 2001 to 2013 within the framework of the Isfahan Cohort Study (ICS). Participants or their family members were interviewed biannually looking for possible events. Cardiovascular events was defined as fatal or non-fatal myocardial infarction (MI), sudden cardiac death, unstable angina and fatal or non-fatal stroke. Total MI, unstable angina and sudden cardiac death defined as CHD. We assessed nuts consumption (walnuts, almonds, pistachios and hazelnuts) using a validated food frequency questionnaire. Cox proportional hazards models were used to examine the association of nut consumption with the CVD events and all-cause mortality.
Results: During the median follow-up of 144 months and 55017 person-years, 751 incident CVD cases including 594 CHD and 157 stroke cases were found. We documented 179 CVD mortality and 458 all-cause deaths. Total nut consumption was inversely associated with CHD, stroke, total CVD, CVD mortality and all-cause death. However after adjustment for age, gender, education, residency, smoking, physical activity, family history of CVD, CVD risk factors, aspirin use and post menopause in women, it were disappeared for all of them except for CVD mortality. According to the multivariable hazard ratio (HR) for CVD mortality, consumption of two or more times/week of nut, compared to the lowest quartile was significantly associated with a 17% 1ower risk of CVD mortality [HR: 0.83; 95% confidence interval (CI): (0.63-0.97); P for trend= 0.04].
Conclusions: We concluded an inverse association between nut intake and lower risk of CVD mortality after full adjustment for potential confounders. Studies with long duration of follow-up considering the types of nuts and preparation methods (raw, roasted or salted) might provide a better level of evidence to establish which kinds of nuts specifically, and to what extent, are responsible for higher influential effects on the risk of CVD and all-cause death.

N Mohammadifard, M Maghroun, F Sajjadi, R Hassannejhad, M Sadeghi, H Roohafza, N Sarrafzadegan

[link url="https://www.sciencedaily.com/releases/2019/08/190831155847.htm"]European Society of Cardiology material[/link]
[link url="https://esc365.escardio.org/Congress/ESC-CONGRESS-2019/Controversies-in-dietary-fat/196353-nut-consumption-the-risk-of-cardiovascular-disease-and-all-cause-mortality-isfahan-cohort-study#abstract"]ESC 2019 abstract[/link]

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