• Dr Emma Derbyshire

Almonds & Health: An Update on the Science


Nuts include tree nuts (almond, Brazil nut, cashew, hazelnut, macadamia, pecan, pine nut, pistachio and walnut) and ground nuts (peanut). The almond is native to Mediterranean climate regions of the Middle East. Nowadays, almonds are widely cultivated throughout the world. Almond production in California is mainly concentrated in the Central Valley, where the mild climate, abundant sunshine, rich soil and water supply allow for ideal growing conditions.


Almonds are the most abundantly consumed tree nut, and contain powerful nutrients, for example they are low on the glycaemic index and high in unsaturated fatty acids, especially oleic acid (18:1) and linoleic acid (18:2). Just 23 almonds (28g) provide 6g of plant based protein, 4g of dietary fibre, 13g of unsaturated fats, an excellent source for alpha‐tocopherol and phytosterols, as well as important vitamins and minerals such as vitamin E, magnesium and potassium.


Almond nutrition research is an ever-growing field, with over 200 scientific publications to date, reporting on areas such as heart health, diabetes, weight management and also the nutrient composition and quality of almonds.


Almonds and Heart Health

Heart disease is currently the number one cause of death worldwide, however, research shows that over 80% of premature deaths from cardiovascular disease could be avoided by changes in diet and lifestyle risk factors, and the current body of research suggests that eating almonds can help maintain a healthy heart and healthy cholesterol levels. In fact, scientific research over the past twenty years has shown that almonds can help maintain a healthy heart and healthy cholesterol levels. Low nut consumption has been contributed to a rise in cardiovascular disease according to a 2016 report of the American Heart Association, and epidemiologic studies have suggested that nut consumption is inversely correlated to cardiovascular risk and all‐cause mortality.


A further study in the US in 2017 examined the individual and combined effects of consuming dark chocolate and cocoa and almonds on markers of coronary heart disease risk. The results of this study demonstrated that consumption of almonds alone, or combined with dark chocolate, improves blood lipid profiles. As such, the inclusion of almonds into a typical Western diet may reduce the risk of coronary heart disease.


It is well reported that a Mediterranean diet is also inversely correlated to cardiovascular risk and a randomised trial of this diet pattern for the primary prevention of cardiovascular disease was conducted in Spain in 2018. The PREDIMED (Prevención con Dieta Mediterránea) trial showed that a Mediterranean diet supplemented with mixed nuts (15 g/d walnuts, 7.5 g/d hazelnuts and 7.5 g/d almonds) reduced the incidence of major cardiovascular events by 28%, compared with the control group that consumed a lower‐fat control diet.


Chylomicrons, also known as ultra-low-density lipoprotein (ULDL), very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) are the five groups of lipoproteins which transport all fat molecules around the body. LDL transporting fat to the cells is known to deposit excess cholesterol into the walls of blood vessels contributing to atherosclerosis, however, research has shown that almonds are able to lower LDL cholesterol in the blood.


A systematic review and meta‐analysis, published in the Journal of Nutritional Science, of 18 randomised controlled trials has determined the effects of almond consumption on blood lipid levels. The results of this review show that almond consumption improves blood lipid levels by decreasing total cholesterol (TC), low‐density lipoprotein cholesterol (LDL‐C) and triglycerides. The evidence from this review strongly indicates that almonds should be encouraged as part of a healthy diet to help maintain healthy blood lipid levels and reduce the risk of heart disease. Further to this study it has been reported that almonds improve other cardiovascular risk factors, such as insulin resistance, oxidative stress, inflammation and endothelial dysfunction.


Almonds and Diabetes

Type 2 diabetes mellitus is a chronic metabolic disease, characterised by glucose intolerance. The incidence and prevalence of type 2 diabetes is rapidly increasing worldwide, and diabetes is a contributing risk factor for other chronic diseases, such as heart disease and stroke. Complications associated with diabetes are the leading causes of morbidity and premature mortality. The use of diet and lifestyle in the prevention, treatment and control of type 2 diabetes is a critical strategy for managing the condition, and both the American Diabetes Association and Diabetes UK have confirmed that a low carbohydrate diet (LCD) is effective in reducing weight, improving blood glucose and regulating blood lipid in patients with type 2 diabetes.


Many randomised controlled studies have been conducted to examine eating almonds in relation to blood glucose control. As such, evidence continues to mount supporting the role of almonds and other tree nuts as part of an overall dietary pattern that is beneficial for those with type 2 diabetes.


The effects of almonds have been conducted in a number of randomised, controlled studies, relating to blood glucose control in patients with type 2 diabetes. These studies have evaluated both post-meal effects and longer-term measures. Results have shown that eating an almond-enriched diet can result in significant reductions in fasting glucose and insulin levels control, when compared to an almond-free diet. Thus, based on the scientific evidence from randomised controlled studies, almonds, when eaten as part of a healthy diet, may have beneficial effects on blood glucose and insulin responses, both in the short term after consuming a meal and over the longer term.


A randomised controlled trial in 2018 studied the effects of almond consumption as part of a LCD in patients with type 2 diabetes. The results show a decrease in the glycated haemoglobin A1c (HbA1c) level in the almond group. Therefore, incorporated almonds into a LCD may improve fasting and postprandial blood glucose among patients with type 2 diabetes.


There is a need to reduce the risk of developing cardiovascular disease for patients with type 2 diabetes. A healthy dietary pattern and regular physical activity are known to be key components of diabetes management. A randomised, crossover, controlled feeding trial in 2017 in patients with type 2 diabetes has shown that almonds incorporated into healthy diets can improve glycemic status in diabetic patients with a better glycemic control. As such, almonds can decrease the glycemic index of co-consumed foods and thus be incorporated into the diet of type 2 diabetes patients in order to reduce the risk of developing cardiovascular disease.


A further study has tested the effect of eating 12 dry roasted almonds 30 minutes prior to a meal, before oral glucose tolerance testing in glucose-intolerant individuals without diabetes. Consuming almonds as an appetiser has shown promise as an option for decreasing postprandial hyperglycaemia in individuals with prediabetes or isolated 1-hour postprandial hyperglycaemia. This study highlights the potential role of almonds as a pre-meal appetizer in the care of prediabetes. Shelled whole almonds can be easily stored and carried and can be eaten before workplace, fast food or restaurant meals.


Almonds and Weight Management

Snacking has become a universal behavioural pattern, with an estimated 94% of Americans snacking at least once a day. To tackle the prevalence of excess weight and obesity, nutrient-rich snack options are required that pose little risk for weight gain. Further to tackling obesity, healthy snacks are required for the growing populations keen to maintain a healthy body and diet. The nutrients in almonds, including monounsaturated fat and fibre, are associated with improved satiety, suggesting they would be an ideal snack for those interested in weight management.


Data from the US Department of Agriculture (USDA) has shown that both roasted and unroasted almonds provide fewer calories than believed. Compared to the number of calories listed on nutrition labels, individuals actually absorbed 25% fewer calories from whole unroasted almonds, 19% fewer calories from whole roasted almonds and 17% fewer calories when almonds were roasted and chopped.


Many randomised controlled studies have been conducted to examine the effects of almonds consumed as part of a healthy diet. The daily consumption of almonds is associated with improving ratings of hunger and satiety in healthy people. As such, a daily handful of almonds is a delicious way to manage cravings and help maintain a healthy body weight. One such study assessed the effect of consuming a mid-morning almond snack (28 and 42g) tested against a negative control of no almonds on acute satiety responses. The scientists reported that intake at lunch and dinner significantly decreased in a dose-dependent manner in response to the almond snacks. As such, almonds might be a healthy snack option since their acute satiating effects are likely to result in no net increase in energy consumed over a day.


Almonds and Colorectal Cancer

Colorectal cancer is a term that combines colon cancer and rectal cancer, and it is currently unknown what causes this disease. There are certain factors that may increase the risk of developing the disease, and include: age, inflammatory bowel conditions, a history of colorectal cancer, diabetes, obesity and a low fibre, high fat diet. As such, research is arising for the potential of almonds to decrease the risk of developing colorectal cancer. One recent case-control study was conducted in Korea in 2018 to determine the relationship between nut intake and risk of colorectal cancer. High nut consumption was strongly associated with reduced risk of colorectal cancer for both men and women. The study results conclude that a favourable association between high frequency of nut consumption and decreased risk of colorectal cancer and concludes that nuts, such as almonds, could be included as part of a healthy diet in order to lower colorectal cancer risk factors.


Conclusions

The potential health benefits of almonds appear to be wide-ranging and include lowering blood sugar levels, reducing blood pressure, lowering cholesterol levels and even reducing the risk of colorectal cancer. Almonds may also reduce hunger and aid weight loss. With a growing body of evidence beginning to establish this makes them an ideal snack suitable for healthy lifestyles.

Image: Almond Trees in Bloom.


References

Lee J et al. (2018) The relationship between nut intake and risk of colorectal cancer: a case control study. Nutr J. 2018 Mar 7;17(1):37

Hou YY et al. (2018) A Randomized Controlled Trial to Compare the Effect of Peanuts and Almonds on the Cardio-Metabolic and Inflammatory Parameters in Patients with Type 2 Diabetes Mellitus. Nutrients. Oct 23;10(11).

Martínez-González MA et al. (2018) Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. N Engl J Med. Oct 4;379(14):1388-1389.

Chen CM et al. (2017) Almonds ameliorate glycemic control in Chinese patients with better controlled type 2 diabetes: a randomized, crossover, controlled feeding trial. Nutr Metab (Lond). Aug 2;14:51.

Lee Y et al. (2017) Effects of dark chocolate and almonds on cardiovascular risk factors in overweight and obese individuals: a randomized controlled-feeding trial. J Am Heart Assoc. 6(12)Crouch MA et al. (2016) Almond “Appetizer” Effect on Glucose Tolerance Test (GTT) Results. J Am Board Fam Med. Nov 12;29(6):759-766.

Mozaffarian D et al. (2016) Executive summary: heart disease and stroke statistics – 2016 update: a report from the American Heart Association. Circulation. 133:447-454.

Musa‐Veloso K et al. (2016) The effects of almond consumption on fasting blood lipid levels: a systematic review and meta‐analysis of randomised controlled trials. J Nutr Sci. 2016;5:e34.

Hull S et al. (2015) A mid-morning snack of almonds generates satiety and appropriate adjustment of subsequent food intake in healthy women. Eur J Nutr. Aug;54(5):803-10.

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