Nut nutrition and health benefit
January 17 2016 by
Ray Sahelian, M.D.

Nuts and seeds are rich in unsaturated fat and other nutrients that may reduce inflammation. Frequent nut consumption is associated with lower levels of inflammatory markers, and lower risk of cardiovascular disease and type 2 diabetes. It is healthier to consume nuts in the raw state as opposed to roasted. When roasted or heated, the fats get altered and could potentially be harmful.
   Nuts are nutrient dense--providing protein, fiber, micronutrients, plant sterols, gamma-tocopherol and other phytochemical compounds, including flavonoids and phenolic compounds. Eating too many can cause weight gain.
   Nuts, including almonds, brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, and walnuts, and peanuts, are rich in phytochemicals, which recently have been found to possess bio-mechanisms against CVD and cancers. Phytochemicals, defined as bioactive non-nutrient components in plant foods, are classified as alkaloids, carotenoids, organosulfurs, phenolics, and phytosterols, while more compounds still remain to be identified and characterized.

Eat raw nuts, not cooked or heated
Nuts have many nutritional benefits: they are high in monounsaturated and polyunsaturated fats, fiber, vitamin, minerals, and phytonutrients. Most contain many minerals, including magnesium. Population studies indicate that individuals who regularly consume nuts have reduced risk for cardiovascular disease and diabetes. In clinical trials, nuts appear to have a neutral effect on glucose and insulin, and a beneficial effect on lipid profile. Thus, nuts can be a healthy dietary component for individuals with diabetes or those at risk for diabetes, providing overall caloric intake is regulated to maintain a healthy body weight.

Health benefit, influence on disease. longevity
Current knowledge on the effects of nut consumption on human health has rapidly increased in recent years and it now appears that nuts may play a role in the prevention of chronic age-related diseases. Frequent nut consumption has been associated with better metabolic status, decreased body weight as well as lower body weight gain over time and thus reduce the risk of obesity. The effect of nuts on glucose metabolism, blood lipids, and blood pressure is still controversial. However, significant decreased cardiovascular risk has been reported in a number of observational and clinical intervention studies.

Nuts are energy-dense foods, with a high content of fat and unsaturated fatty acids. The favorable fatty acid profile probably contributes to the beneficial effects of nut consumption in prevention of coronary heart disease and diabetes and cholesterol lowering. Besides fat, nuts have several beneficial substances including vegetable protein, fiber, minerals, tocopherols, and phenolic compounds. Nuts are likely to lower or have a beneficial effect on LDL cholesterol oxidation, soluble inflammatory molecules, and endothelial dysfunction. Nut consumption is associated with lower concentrations of circulating inflammatory molecules and higher plasma adiponectin, a potent anti-inflammatory adipokine.

A large study announced in November 2013 showed that people who ate nuts every day were less likely to die from heart disease, cancer or any other cause over 30 years than people who didn’t eat them, according to Dana-Farber Cancer Institute, Brigham and Women’s Hospital, and the Harvard School of Public Health. Nut consumption is associated with reduced risk of coronary artery disease.

Teens who eat a modest amount of nuts daily have a lower risk of getting metabolic syndrome, a cluster of conditions, such as high blood pressure and high blood sugar, that raises the risk of heart disease and diabetes. San Diego.JAMA Internal Medicine, March 2, 2015.

Blood pressure, hypertension
Am J Clin Nutr. 2015. The effect of tree nut, peanut, and soy nut consumption on blood pressure: a systematic review and meta-analysis of randomized controlled clinical trials. Although several studies have assessed the effects of nut consumption (tree nuts, peanuts, and soy nuts) on blood pressure (BP), the results are conflicting. Total nut consumption lowered SBP in participants without type 2 diabetes. Pistachios seemed to have the strongest effect on reducing systolic blood pressure and DBP. Mixed nuts also reduced DBP.

Influence on cholesterol levels
Eating nuts can lead to healthier cholesterol levels, but the benefits seem to be greatest for thinner people, those eating less healthy diets, and people with higher levels of "bad" LDL cholesterol and triglycerides. Archives of Internal Medicine, May 2010.

Brain function, mental health
A Mediterranean diet supplemented by nuts or olive oil was associated with improved cognitive function in people aged 55-80 years, according to Cinta Valls-Pedret of the Institut d'Investigacions Biomèdiques, published in 2015.

Nuts in the diet good fro heart health
A traditional Mediterranean diet that includes a healthy serving of nuts each day may help reverse a number of risk factors for heart disease. In a study of more than 1,200 older adults, researchers from Spain found that those who followed the diet had lower rates of metabolic syndrome -- a clustering of risk factors for heart disease, diabetes and stroke, which includes high blood pressure, abdominal obesity, elevated blood sugar and unhealthy cholesterol levels. Archives of Internal Medicine, 2008.

Sense of smell, olfactory improvement
Br J Nutr. 2015. Dietary intakes of fats, fish and nuts and olfactory impairment in older adults. It is unclear whether lifestyle modifications, such as dietary changes, should be advocated to prevent olfactory dysfunction. We investigated the association between dietary intakes of fats (saturated, mono-unsaturated and polyunsaturated fats, and cholesterol) and related food groups (nuts, fish, butter, margarine) with olfactory impairment. Older adults with the highest consumption of nuts and fish had reduced odds of olfactory impairment.

When people change from their habitual diet to an almond supplemented diet, their intakes of MUFA, PUFA, fiber, vegetable protein, alpha-tocopherol, Copper and magnesium increases  while their intake of trans fatty acids, animal protein, sodium, cholesterol and sugars decrease.
   It is preferable to consume almonds raw as opposed to roasted. Asparagine is the main free amino acid in raw almonds and is correlated with the acrylamide content of dark roasted almonds.

Areca Nut - Betel
Areca-nut chewing occurs widely in South Asia and the Indian subcontinent. Arecoline, the principal neuroactive alkaloid, is found in a mother's placenta if she is a chronic areca nut user. Neonatal withdrawal syndrome can occur in an infant born to a woman who is a chronic areca-nut user.
     In addition to increasing the risk of developing oral cancer, betel nut chewing appears to be related with another health hazard: obesity.

Brazil Nut health benefit
Brazil nuts contain a high amount of selenium and magnesium. Allergy to Brazil nut is a relatively common nut allergy and can be fatal. A combination of history, skin prick test and serum-specific IgE is often adequate in achieving a diagnosis in the majority of patients with suspected Brazil nut allergy.

Brazil nuts: an effective way to improve selenium status.
Am J Clin Nutr. 2008. Department of Human Nutrition, University of Otago, Dunedin, New Zealand.
We investigated the efficacy of Brazil nuts in increasing selenium status in comparison with selenomethionine. Participants consumed 2 Brazil nuts thought to provide approximately 100 mug Selenium, 100 mug Selenium as selenomethionine, or placebo daily for 12 wk. Actual intake from nuts averaged 53 mug selenium /d (possible range: 20-84 mug Se). Plasma selenium and plasma and whole blood glutathione peroxidase (GPx) activities were measured at baseline and at 2, 4, 8, and 12 wk, and effects of treatments were compared. Plasma selenium increased by 64%, 61%, and 7%; plasma glutathione peroxidase by 8%, 3%, and -1%; and whole blood glutathione peroxidase by 13%, 5%, and 1.9% in the Brazil nut, selenomethionine, and placebo groups, respectively. Consumption of 2 Brazil nuts daily is as effective for increasing selenium status and enhancing GPx activity as 100 mug Se as selenomethionine. Inclusion of this high-selenium food in the diet could avoid the need for fortification or supplements to improve the selenium status of New Zealanders.

Q. Down here in New Zealand some of us have some doubts about the brazil nut study you mentioned. See the comment below published in one of our general interest magazines. As a low selenium environment I am afraid we cannot rely on getting enough from food. I am a doctor here in Tauranga. Here is the article: "Further to my letter on the Selenium content of brazil nuts, I have been referred to research on the selenium content of nuts from different sources. One such article in the journal of Food Safety presents the results from 72 different brazil nuts in stores. Their average selenium content was 14.7 micrograms per gram with a range of 0.2- to 253. If two brazil nuts weighed 10 grams the amount of selenium supplied would vary from a totally inadequate 2 mcg to a possibly toxic 2530 mcg. All we knew about selenium until 1958 was that herbage on some soils relatively rich in the mineral took up so much that the animals suffered from selenium poisoning. This makes nonsense of the recent recommendation in a research publication from the department of human nutrition, University of Otago - "brazil nut: an effective way to improve selenium status." American Journal of Clinical Nutrition{ 2008, p 379} - which concludes "consumption of two brazil nuts daily is as effective for increasing selenium status as 100 micrograms Se as selenomethionine. Inclusion of this high selenium food in the diet could avoid the need for fortification or supplements to improve the selenium status of New Zealanders."
Two recent samples recently bought contained 2.6 and 29 mcg of selenium per gram of brazil nut My advice is not to rely on brazil nuts unless their selenium content is known. Professor Thomas John Walker, Halswell Christchurch.
   A. This is interesting. I think it is quite safe to ingest one Brazil nut, no matter from what source a day or two a week.

Could you please comment on Brazil nuts and their radioactive content in relation to health?
    The radioactive content of these nuts is not an area of concern as far as health is concerned. Brazil nuts are high in fat and calories and for this reason consuming one to three items a couple of times a week is reasonable.

Cashew Nut Anacardium occidentale has about 7 calories each
Cashew nut allergy can be of concern. Anaphylaxis to cashew nut is more common than to peanut. Children with cashew allergy are at risk of anaphylaxis.

Hazel Nut
Hazelnuts have a high amount of tocopherols and tocotrienols.


Kukui nut is popular in Hawaii and used topically for psoriasis although little research exists to substantiate the effectiveness of kukui nut oil applied topically for the treatment of psoriasis.


Peanut and Allergy
A skin prick result > or = 8 mm or a specific IgE > or = 15 kU A /L have a high predictive value for clinical allergy to peanut and that these cutoff figures appear generalizable to different populations of children undergoing an assessment for peanut allergy.
      Treatment of peanut allergic mice with the Chinese herbal formula known as FAHF-2 completely blocks peanut-induced allergic reactions for up to 6 months following therapy and full protection is restored following a second course of FAHF-2. These observations, if reproducible in humans, suggest that this Chinese herbal formula may be a highly effective treatment for peanut allergy. Following treatment with FAHF-2 for 7 weeks, peanut-allergic mice were completely protected against peanut-induced reactions following oral challenges administered up to 34 weeks after treatment. The research team is working to identify the bioactive compounds present in the formula. How FAHF-2 works remains unclear. Preliminary work indicates that FAHF-2 may target multiple cell types known to be involved in allergic reactions. FAHF-2 also appears to stimulate T cells to produce more interferon-gamma, a cytokine that is known to curb allergic responses.


Pine Nut
A compound in Korean pine tree nuts may act as an appetite suppressant. A UK study was done on the effect of commercially produced pine nut oil in 18 overweight women. These volunteers were randomly divided into a group that received gel capsules containing either Lipid Nutrition's PinnoThin pine oil product or olive oil, before eating a carbohydrate-rich breakfast of white bread and orange marmalade. One week later the researchers repeated the experiment, giving pine nut oil-containing capsules to the women who originally consumed olive oil and vice versa. The oil in the pine nuts appeared to promote the release of cholecystokinin (CCK) and glucagon-like peptide (GLP-1), two gastrointestinal hormones that are known to send "satiety signals" - i.e. signals that the stomach is feeling full - to the brain. After taking the pine nut oil-containing capsules, the women reported a lower desire to eat and a desire to eat less food during their next meal than they did after consuming the olive oil supplements. Pine nuts in general are a good source of protein and healthy fats, particularly for vegetarians. Apparently Korean pine nut is contains much higher levels of the polyunsaturated fats than do other nuts.
   Press release from Source Naturals - Korean pine nuts are a rich source of pinolenic acid, which may increase concentrations of the satiety hormones glucogon-like peptide-1 (GLP-1) and cholecystokinin (CCK). A small-scale study suggests that Source Naturals PineSlim, containing PinnoThin may reduce feelings of hunger by increasing concentrations of appetite-suppressing hormones.

Nutr Rev. 2012. Pistachio nuts: composition and potential health benefits. The pistachio is a nutrient-dense nut with a heart-healthy fatty-acid profile as well as protein, dietary fiber, potassium, magnesium, vitamin K, γ-tocopherol, and a number of phytochemicals. The pistachio's unique green and purple kernel color is a result of its lutein and anthocyanin content. Among nuts, pistachios contain the highest levels of potassium, γ-tocopherol, vitamin K, phytosterols, and xanthophyll carotenoids. Five published randomized cardiovascular trials have shown that pistachios promote heart-healthy blood lipid profiles. Exploratory clinical studies suggest that pistachios help maintain healthy antioxidant and anti-inflammatory activity, glycemic control, and endothelial function.

2009 - bioactive compounds in pistachios, and molecules present in pistachios, have anti-inflammatory properties. Pistachio oil decreases levels of an inflammatory marker known as "Ifit-2" (INF-induced protein with tetratricopeptide repeats 2). Inflammation is a complex biological response to harmful stimuli, pathogens, damaged cells or irritants, and it underlies functional changes associated with many chronic diseases, such as obesity and cancer. The study, published in Molecular Nutrition & Food Research, found that pistachio oil significantly affects genes involved in immune response, defense response to bacteria and gene silencing. The Western Pistachio Association has long promoted that, when incorporated into a daily diet, pistachios have a beneficial effect on lipid and lipoprotein profiles. Pistachios are a naturally cholesterol-free snack that contains just 1.5 grams of saturated fat and 13 grams of fat, the majority of which comes from monounsaturated fat. A one-ounce serving of pistachios equals 49 nuts, which is more nuts per serving than any other snack nut. One serving of pistachios has as much potassium (300mg, 8%) as an orange (250mg, 7%), making it a nutritious snack choice or ingredient to incorporate into daily diets.

Pistachios Increase Serum Antioxidants and Lower Serum Oxidized-LDL in Hypercholesterolemic Adults.
J Nutr. 2010. Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA.
Pistachios are high in lutein, beta-carotene, and gamma-tocopherol relative to other nuts; however, studies of the effects of pistachios on oxidative status are lacking. We conducted a randomized, crossover controlled-feeding study to evaluate 2 doses of pistachios on serum antioxidants and biomarkers of oxidative status in 28 hypercholesterolemic adults. Participants consumed 3 isoenergetic diets for 4 wk each after a 2-wk baseline Western diet. Experimental diets included a lower-fat control diet without pistachios (25% total fat) with 1 serving/d (i.e. 32-63 g/d; energy adjusted) of pistachios (1 PD; 10% energy from pistachios; 30% total fat) or with 2 servings/d (63-126g/d; energy adjusted) of pistachios (2 PD; 20% energy from pistachios; 34% total fat). When participants consumed the pistachio-enriched diets, they had higher plasma lutein, alpha-carotene, and beta-carotene concentrations than after the baseline diet. After consuming the pistachio diets, participants had greater plasma lutein and gamma-tocopherol relative to the lower-fat control diet. After the 2 PD diet period, participants also had lower serum oxidized-LDL concentrations than following the baseline diet period. After both the 1 PD and 2 PD diet periods, they had lower serum oxidized-LDL concentrations than after the control diet period. A heart-healthy diet including pistachios contributes to the decrease in the serum oxidized-LDL concentration through cholesterol-lowering and may provide an added benefit as a result of the antioxidants the pistachios contain.

Nutrition. 2013. Bioaccessibility of pistachio polyphenols, xanthophylls, and tocopherols during simulated human digestion. The bioaccessibility of bioactives from pistachios has not been previously evaluated. In the present study we quantified the release of polyphenols, xanthophylls (lutein), and tocopherols from pistachios (raw pistachios, roasted salted pistachios, and muffins made with raw pistachios) during simulated human digestion. A dynamic gastric model of digestion that provides a realistic and predictive simulation of the physical and chemical processing and accurately mimics the residence time and the luminal environment within the human stomach was used for the digestion studies. More than 90% of the polyphenols were released in the gastric compartment, with virtually total release in the duodenal phase. No significant differences were observed between raw shelled and roasted salted pistachio. The presence of a food matrix (muffin) decreased the bioaccessibility of protocatechuic acid (78%) and luteolin (36%). Almost 100% bioaccessibility of lutein and tocopherols was found after duodenal digestion, with no difference among the three samples. :The rapid release of the assayed bioactives in the stomach maximizes the potential for absorption in the duodenum and contributes to the beneficial relation between pistachio consumption and health-related outcomes.

Walnut health benefit
Consumption of nuts has been associated with a decreased risk of cardiovascular disease events and death. Walnuts in particular have a unique profile: they are rich in polyunsaturated fatty acids, which may improve blood lipids and other cardiovascular disease risk factors. A diet that includes walnuts delivering polyunsaturated fatty acids can improve the lipid profile of patients with type 2 diabetes.

Nuts and Fats
Nuts are high in fat but have a fatty acid profile that may be beneficial in relation to risk of coronary heart disease. Nuts also contain other potentially cardioprotective constituents including phytosterols, tocopherols and squalene. A study was conducted to determine the total oil content, peroxide value, composition of fatty acids, tocopherols, phytosterols and squalene content in the oil extracted from freshly ground walnuts, almonds, peanuts, hazelnuts and the macadamia nut. The total oil content of the nuts ranged from 38 to 602%. The main monounsaturated fatty acid was oleic acid (C18:1) with substantial levels of palmitoleic acid (C16:1) present in the macadamia nut. The main polyunsaturated fatty acids present were linoleic acid (C18:2) and linolenic acid (C18:3). alpha-Tocopherol was the most prevalent tocopherol except in walnuts. The levels of squalene detected ranged from 9 to 186 microg/g. beta-Sitosterol was the most abundant sterol, ranging in concentration from 991 to 2071 microg/g oil. Campesterol and stigmasterol were also present in significant concentrations. All five nuts are a good source of monounsaturated fatty acid, tocopherols, squalene and phytosterols.

Phytosterols in nuts and seeds
Sesame seeds and wheat germ have the highest total phytosterol content (400-413 mg/100 g) and Brazil nuts the lowest (95 mg/100 g). Of the products typically consumed as snack foods, pistachio nuts and sunflower kernel are richest in phytosterols (270-289 mg/100 g). beta-Sitosterol, Delta5-avenasterol, and campesterol are predominant.

Q. I am writing a book on polyphenols and mention of tannins in nuts. Can you give me one good quotation about the polyphenols in nuts (same as chocolate, coffee, and red wine?) and how they work to stave off disease (which ones)? In easy lay person terminology.
   A. Polyphenol antioxidants found in nuts are able to inhibit cholesterol and lipid oxidation, thus potentially reducing the risk for hardening of the arteries. In rodent studies, nut polyphenols are able to reduce the risk of cancer in the lung, liver, skin and esophagus and probably other sites. Frequent nut consumption is associated with lower levels of inflammatory markers, and lower risk of cardiovascular disease and type 2 diabetes.

Effect of nut consumption on plasma polyphenol, antioxidant capacity and lipid peroxidation of healthy humans
The FASEB Journal. 2008
To assess the immediate effect of treatment meal (75% of energy from nuts: walnut or almond) and control meal (nut free meal) on plasma polyphenols levels, antioxidant capacity and lipid peroxidation in healthy volunteers. Thirteen subjects participated in a randomized, crossover, intervention study. After an overnight fast, walnut, almond or control meal in the form of smoothies were consumed by study subjects. Each subject participated on three occasions one week apart, consuming one of the smoothies each time. There was a significant increase in plasma polyphenol concentration following both the nut meals, with peak concentrations reaching at 90 min, with walnut meal having a more sustained higher concentration than almond meal. The plasma total antioxidant capacity determined reached its highest point at 150 min post-consumption of the nut meals, and was higher after the almond compared to walnut meal. A gradual significant reduction in the susceptibility of plasma to lipid peroxidation was observed 90 min after ingestion of the nut meals. No changes were observed following consumption of control meal. Consumption of both nuts increased plasma polyphenol concentrations, increased the total antioxidant capacity and reduced plasma lipid peroxidation.

Nuts and Cholesterol
Consumption of approximately 50-100 g (approximately 1.5-3.5 servings) of nuts a few  times a week as part of a heart-healthy diet with total fat content (high in mono- and/or polyunsaturated fatty acids) of approximately 35% of energy may decrease total cholesterol and LDL cholesterol.

Nuts and Heart Attack
A European study says eating nuts, including peanuts, can help reduce risk of coronary heart disease. For the first time, the association between nut consumption and health in nearly 400,000 Europeans has been studied to take account of the different dietary habits and nut intake patterns between Americans and Europeans. The researchers identified that nearly half of Europeans rarely consume nuts, yet an intake of just two servings of nuts per week, where each serving is about a handful -- one ounce -- may reduce risk of death from coronary heart disease by 11 percent. "The important thing is that very modest consumption is associated with protection," said Elio Riboli, professor of cancer epidemiology at Imperial College in London. "A small plate of nuts with a glass of wine would be a healthy amount. A classic aperitif accompanied by a dish of nuts at least twice a week would be an ideal combination."

Nut and cancer
The potential of nuts in the prevention of cancer.
Br J Nutrition. 2006. Human Nutrition Unit, Faculty of Medicine and Health Sciences, Rovira i Virgili University, Reus, Spain.
Like fruits and vegetables, nuts are a source of vegetable protein, monounsaturated fatty acids, vitamin E, phenolic compounds, selenium, vegetable fibre, folic acid and phytoestrogens. There are numerous mechanisms of action by which these components can intervene in the prevention of cancer, although they have not been fully elucidated. There are very few epidemiological studies analyzing the relationship between nuts consumption and risk of cancer. One of the greatest difficulties in interpreting the results is that the consumption of nuts, seeds and legumes are often presented together. The most commonly studied location is the colon / rectum, an organ in which the effect of nuts is biologically plausible. Although the results are not conclusive, a protective effect on colon and rectum cancer is possible. Likewise, some studies show a possible protective effect on prostate cancer, but there is insufficient data on other tumour locations. New epidemiological studies are required to clarify the possible effects of nuts on cancer, particularly prospective studies that make reliable and complete estimations of their consumption and which make it possible to analyse their effects independently of the consumption of legumes and seeds.

Body Weight
Nuts are foods with a high energy density, due in part to their low water content. They also present a low saturated fat content (<7%) but a high unsaturated fat contribution (40-60%). Nuts represent one of the richest sources of dietary fiber, mostly of the insoluble type. The effects of nut intake on health have been widely studied. Some studies have focused on the effect of nuts on body weight. At present, no evidences support a detrimental effect of nut consumption on body weight. On the contrary some weight loss studies suggest a beneficial effect of nut intake on body weight regulation.

Frequent nut consumption is associated with a reduced risk of gallstone disease.

We also have information on beans.

Nut Research
Chemical composition of selected edible nut seeds.
J Agric Food Chem. 2006. Department of Nutrition, Food & Exercise Sciences, Florida State University, Tallahassee, Florida
Commercially important edible nut seeds were analyzed for chemical composition and moisture sorption. Moisture (1.4-9%), protein (7.5-21%), lipid (42-66%), ash (1-3%), total soluble sugars (0.55-3.9%), tannins (0.01-0.88%), and phytate (0.15-0.3%) contents varied considerably. Regardless of the seed type, lipids were mainly composed of mono- and polyunsaturated fatty acids (>75% of the total lipids). Fatty acid composition analysis indicated that oleic acid was the main constituent of monounsaturated lipids in all seed samples. With the exception of macadamia, linoleic acid (C(18:2)) was the major polyunsaturated fatty acid. In the case of walnuts, in addition to linoleic acid (59.79%) linolenic acid (C(18:3)) also significantly contributed toward the total polyunsaturated lipids. Amino acid composition analyses indicated lysine (Brazil nut, cashew, hazelnut, pine, and walnut), sulfur amino acids methionine and cysteine (almond), tryptophan (macadamia, pecan), and threonine (peanut) to be the first limiting amino acid as compared to human (2-5 year old) amino acid requirements.