Nuts - HEART UK

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Systematic reviews and meta-analyses have consistently shown that eating around 28g of nuts a day can significantly reduce cardiovascular disease risk and improve serum lipid biomarkers^1-4.  

Take home messages

The term 'nuts' on this page refers to both tree nut and peanuts.
A daily handful of nuts (28g), unsalted and unsweetened, has been proven to lower LDL cholesterol and reduce CVD risk by up to 21%.
It is the nutrient profile of nuts that contributes to improved lipids and cardiovascular health: they are rich in unsaturated fats, a variety of fibres, plant sterols, minerals including potassium and magnesium, and the antioxidant vitamins beta-carotene and vitamin E.
Nut consumption has also been associated with improved weight management and satiety. And despite their higher energy density, research has proven that regular nut consumption is not associated with increased body weight.

The wealth of evidence resulted in the FDA approving the health claim: “consumption of 1½oz (42g) of nuts [a day], as part of a low saturated fat and cholesterol diet, may reduce the risk of heart disease”⁵.

What is the evidence?

Nuts and blood lipids

Two meta-analyses have investigated the impact of eating more nuts on blood fats.

The first meta-analysis included 25 small intervention trials with a cross-over or parallel design, and involved 583 patients with normal or raised cholesterol⁶. Over a 3-8 week period, the intervention groups ate on average 67g of nuts a day.

The nut intervention led to a reduction of 5.1% in total cholesterol and 7.4% in LDL cholesterol. Notably, this effect was more pronounced in individuals with higher baseline cholesterol levels and body mass index (BMI). There were no significant changes in high-density lipoprotein (HDL) cholesterol and triglyceride levels.

67g daily nut consumption is a rather large serving, but further analysis identified a dose-dependent relationship. A more practical daily amount of approximately 35g, equivalent to 10% of total daily energy intake, could be expected to cause a reduction of 2.8% in total cholesterol and 4.2% in LDL cholesterol.

A 2015 meta-analysis of 61 controlled trials, involving 2,582 participants, found improved lipid profiles among those eating 28g of nuts daily for 3-26 weeks compared to controls. 28g a day brought about reductions of 0.12mmol/L for both total and LDL cholesterol, 0.1mmol/L for ApoB, and 0.02mmol/L for triglycerides³.

Nuts and cardiovascular disease risk

Numerous meta-analyses of intervention trials have consistently supported the cardioprotective benefits of regularly eating nuts.

A 2014 meta-analysis demonstrated a reduced relative risk of 22% for non-fatal and 24% for fatal ischaemic heart disease when individuals ate 28g of nuts four times a week⁷.
Two years later, another meta-analysis of 20 prospective cohort studies with over 315,000 participants found that those who ate approximately 28g of various nuts or peanuts had a 29% lower risk of CHD and a 21% lower risk of CVD compared to low nut consumers¹.
A 2018 systematic review and meta-analysis pooling data from well-established cohort studies, including the Adventist, nurses', and physicians' health studies, found a 14% reduced risk of CVD and a 20% reduction in CHD when 28g of nuts were consumed five or more times a week⁸.
In the same year, a re-analysis of the PREDIMED trial, focusing on a high cardiovascular disease risk population following a Mediterranean diet with a daily intake of 30g of mixed nuts, reported a 28% reduced risk of major cardiovascular events after five years of follow-up⁹.
And finally, a 2023 umbrella review, using data from intervention and cohort studies, demonstrated an overall 21% and 25% relative risk reduction for CVD and CHD with a daily intake of 28g of nuts, with little variation between the type of nut consumed¹⁰.

Proposed mechanisms

The cardioprotective effect has been attributed to the nutrition profile of nuts. They are rich in unsaturated fats, a variety of fibres, plant sterols, minerals including potassium and magnesium, and the antioxidant vitamins beta-carotene and vitamin E^1,8,10.

The effective dose? 28g daily

Which nuts?

Studies have investigated the impact of peanuts and a variety of tree nuts including pecans, cashews, hazelnuts, almonds, Brazil nuts, walnuts, cashews and pistachios. The evidence demonstrates no difference in effect with different types of nuts^{1–4,6,10,11}.

Nuts and concerns about weight gain

There is a common misconception that the high calorie content of nuts, mainly due to their unsaturated fat content, could lead to weight gain and may not be suitable for people with a high BMI. However, the pooled data from large meta-analyses comparing daily nut consumers with non-consumers, consistently demonstrates no association with weight gain or higher BMI^3,11,12.

The evidence suggests that up to 30% of the calories in nuts remains unabsorbed by the human body. Furthermore, nuts have satiating properties, with those who ate nuts reporting extended feelings of fullness and eating less at subsequent meals.

Watch our CPD e-module: The four cholesterol lowering foods

Read about the other cholesterol-lowering foods

Oats and barley Soya Sterols and stanol esters

References

Coates A, Hill A, Tan S. Nuts and Cardiovascular Disease Prevention. Curr Atheroscler Rep. 2018;20(10):48. doi:10.1007/s11883-018-0749-3
Aune D, Keum N, Giovannucci E, et al. Nut consumption and risk of cardiovascular disease, total cancer, all-cause and cause-specific mortality: a systematic review and dose-response meta-analysis of prospective studies. BMC Medicine. 2016;14(1):207. doi:10.1186/s12916-016-0730-3
Del Gobbo LC, Falk MC, Feldman R, Lewis K, Mozaffarian D. Effects of tree nuts on blood lipids, apolipoproteins, and blood pressure: systematic review, meta-analysis, and dose-response of 61 controlled intervention trials 123. The American Journal of Clinical Nutrition. 2015;102(6):1347-1356. doi:10.3945/ajcn.115.110965
Balakrishna R, Bjørnerud T, Bemanian M, Aune D, Fadnes LT. Consumption of Nuts and Seeds and Health Outcomes Including Cardiovascular Disease, Diabetes and Metabolic Disease, Cancer, and Mortality: An Umbrella Review. Advances in Nutrition. 2022;13(6):2136-2148. doi:10.1093/advances/nmac077
Center for Food Safety and Applied Nutrition. Labeling & Nutrition - Qualified Health Claims: Letter of Enforcement Discretion - Nuts and Coronary Heart Disease (Docket No 02P-0505). FDA. Published January 14, 2003. Accessed October 12, 2023. http://wayback.archive-it.org/7993/20171114183724/https://www.fda.gov/Food/IngredientsPackagingLabeling/LabelingNutrition/ucm072926.htm
Sabaté J, Oda K, Ros E. Nut Consumption and Blood Lipid Levels: A Pooled Analysis of 25 Intervention Trials. JAMA. 2010;170(9):821-827.
Afshin A, Micha R, Khatibzadeh S, Mozaffarian D. Consumption of nuts and legumes and risk of incident ischemic heart disease, stroke, and diabetes: a systematic review and meta-analysis. Am J Clin Nutr. 2014;100(1):278-288. doi:10.3945/ajcn.113.076901
Bitok E, Sabaté J. Nuts and Cardiovascular Disease. Progress in Cardiovascular Diseases. 2018;61(1):33-37. doi:10.1016/j.pcad.2018.05.003
Estruch R, Ros E, Salas-Salvadó J, et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. New England Journal of Medicine. 2018;378(25):e34. doi:10.1056/NEJMoa1800389
Glenn AJ, Aune D, Freisling H, et al. Nuts and Cardiovascular Disease Outcomes: A Review of the Evidence and Future Directions. Nutrients. 2023;15(4):911. doi:10.3390/nu15040911
Kim Y, Keogh J, Clifton PM. Nuts and Cardio-Metabolic Disease: A Review of Meta-Analyses. Nutrients. 2018;10(12):1935. doi:10.3390/nu10121935
Baer DJ, Dalton M, Blundell J, Finlayson G, Hu FB. Nuts, Energy Balance and Body Weight. Nutrients. 2023;15(5):1162. doi:10.3390/nu15051162

Published: June 2024