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Nutrition Nuts

July 10, 2009 Written by JP    [Font too small?]

One of my primary goals for this site is to provide practical and topical information that can be incorporated into daily life. The following research has all been published within the past seven months. 2009 may ultimately be considered the “year of the nut” thanks to the extensive coverage that science is devoting to this humble snack food. By looking at the current batch of studies and data collected over the last few decades, it’s become abundantly clear that regular nut consumption can help address some of the biggest health crises facing our society, namely diabetes, heart disease and obesity. The best news of all is that every one of us can easily adjust our diets to derive all of the benefits that nuts have to offer.

For starters I’d like to review a few articles that summarize some of the key benefits of nut consumption in a real world setting. The primary source of information used in this type of analysis is derived from studying the eating patterns and disease prevalence of large segments of the community. The purpose for doing so is to try to discover patterns that can possibly be applied to the population as a whole. Two scientific papers focusing on the health effects of nuts appeared in the May 2009 issue of the American Journal of Clinical Nutrition. (1,2) This is a brief summary of the conclusions:

  • The specific types of fat contained in nuts are likely responsible for much of their cholesterol lowering effect, cardioprotective properties and the unique benefits demonstrated in diabetics.
  • Other components of nuts, such as fiber, mineral and protein content along with naturally occurring antioxidants may specifically support arterial health, endothelial function and combat inflammation.
  • Preliminary evidence appears to point to a more potent anti-cancer and diabetes countering effect in women. Gallstone prevention has been demonstrated in both sexes.
  • Regular, long term nut intake is associated with healthy weight and reduced risk for obesity and weight gain.

Walnuts are often the recipients of scientific attention because, unlike other nuts, they’re a relatively rich source of omega-3 fatty acids. Fish is generally a heart healthy food, largely because it also contains high amounts of similar types of fat. Recently, a study compared the effects of diets containing either fish or walnuts in a group of volunteers with mild hyperlipidemia (high cholesterol and triglycerides). In this experiment, the participants were fed three different diets during separate 4 week periods. All the diets contained approximately 30% total fat and less than 10% saturated fat:

  • Diet 1 – Included 4 ounces of salmon twice a week
  • Diet 2 – Featured about 1.5 ounces of walnuts twice weekly
  • Diet 3 – The placebo diet contained no fish or nuts

Blood tests were performed at the beginning and end of each diet. The results revealed that the walnut diet lowered LDL “bad” cholesterol more effectively than the fish. But the fish diet reduced triglycerides and raised HDL “good” cholesterol to a greater extent than the walnut diet. (3) These results are consistent with a just published meta-analysis of the “effects of walnut consumption on blood lipids”. That review of 13 studies also found lower LDL levels but no significant alterations in HDL cholesterol or triglycerides. (4) Part of the reason for this could be that fish contains two specific omega-3 fats, known as DHA and EPA, which are not present in nuts or other plant based foods. Based on these results, it would seem prudent to include both types of food as a regular part of the diet.

Nuts have recently been promoted as a type of food that may protect against heart dysfunction relating to metabolic syndrome (see image below). (5) They have also been singled out, along with vegetable intake and a Mediterranean style diet, in a comprehensive summary of foods that are linked to cardiovascular protection. (6) One of the more interesting studies of late looked at the dietary patterns of a group of over 237,000 physicians. That targeted population study found that doctors that ate the largest amounts of nuts had the lowest risk of hypertension (high blood pressure). (7) Another trial found that both almonds and walnuts increased the antioxidant activity in a group of healthy volunteers and helped protect against “lipid peroxidation”, which is believed to contribute to the progression of cardiovascular disease. (8)

Heart disease is one of the greatest health risks in the population at large, but it is an even greater threat to those with type 2 diabetes. The July 2009 edition of the Journal of Nutrition examined the impact of nut intake in a group of 6,300 women with type 2 diabetes. The analysis was based on 22 years of food frequency questionnaires and the relative incidence of coronary heart disease (CHD). The results demonstrated that women who ate at least 5 weekly servings of nuts and/or peanut butter were about 44% less likely to be diagnosed with CHD. A serving was classified as 1 ounce of nuts and/or 1 tablespoon of peanut butter. (9) Another benefit that nuts provide is that they appear to improve insulin sensitivity. (10) Proper blood sugar management is an important factor in the prevention of cardiovascular complications in diabetics.

Finally, I’d like to dispel a common notion about nuts and weight gain. It’s true that nuts and seeds are calorically dense. I can’t deny that they’re also high in fat. But what I can tell you is that science simply does not support the theory that eating nuts promotes weight gain. In fact, the exact opposite is true – provided that a little common sense is factored into the equation.

In June, a trial was published that looked for a connection between nut intake and weight fluctuations. Almost 52,000 women (20-45 years of age) were followed from 1991 to 1999. The bad news is that, on average, most of the women gained weight. The good news is that those eating 2 or more servings of nuts (peanuts or tree nuts) per week gained less weight. The authors of the research also noted that the frequent nut eaters were less likely to be classified as being obese. The concluding remarks read as follows, “The results of this study suggest that incorporating nuts into diets does not lead to greater weight gain and may help control weight”. (11)

Furthermore, a Scandinavian study discovered that snacking on an equal amount of calories from peanuts instead of candy resulted in some very different outcomes. A group of 11 men and 14 women demonstrated that eating a set amount of peanuts for 14 days did not lead to significant weight gain or increase in waist circumference, but eating the same amount of calories from candy did. In addition, cardiovascular markers worsened in those eating the candy snacks. Another difference found was that those eating peanuts exhibited an improvement in their metabolic rate – they burned more calories! (12) Perhaps this is why experts in England are recommending the replacement of one “unhealthy snack” with nuts in order to drastically reduce the incidence of “cardiovascular deaths” in the UK. (13)

You may be wondering if there is any downside to eating nuts. Provided that you’re not allergic to them and that you eat them in moderation, I can’t think of a reason not to include in your diet. The evidence of a positive connection between the consumption of nuts and the likelihood of a healthier life is pretty overwhelming. So make it a point to replace some unhealthier foods with a handful of nuts that may help you to maintain or reclaim your wellness.

Note: Please check out the “Comments & Updates” section of this blog – at the bottom of the page. You can find the latest research about this topic there!

Be well!


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Posted in Food and Drink, Heart Health, Nutrition

10 Comments & Updates to “Nutrition Nuts”

  1. Christina Crowe Says:

    Great post! I actually included some information about walnuts in my article Secrets of Breast Cancer Revealed:

    Not only do walnuts lower cholesterol, but they reduce breast cancer risks, which is another reason why I plan on adding these tasty snacks into my diet.

  2. JP Says:

    Thanks, Christina!

    Way to spread the word!

    Be well!


  3. julie Says:

    Nuts are great, for example, RAW almonds help with indigestion and heartburn. Next time you eat too much pizza or red sauce, instead of grabbing the TUMS, go eat some healthy *raw* almonds..

    you’ll be surprised with the results


  4. JP Says:


    I agree that almonds can be great for the digestive system.

    Good suggestion. I hope someone tries it and reports back!

    Be well!


  5. JP Says:

    Update 06/05/15:


    Nutrition Journal 2015, 14:54

    Improvement of antioxidant status after Brazil nut intake in hypertensive and dyslipidemic subjects

    Objectives: To investigate the effect of partially defatted Granulated Brazil nut (GBN) on biomarkers of oxidative stress and antioxidant status of hypertensive and dyslipidemic patients on nutrition and drug approaches.

    Methods: Ninety one hypertensive and dyslipidemic subjects of both genders (51.6 % men), mean age 62.1 ± 9.3 years, performed a randomized crossover trial, double-blind, placebo controlled. Subjects received a diet and partially defatted GBN 13 g per day (≈227.5 μg/day of selenium) or placebo for twelve weeks with four-week washout interval. Anthropometric, laboratory and clinic characteristics were investigated at baseline. Plasma selenium (Se), plasma glutathione peroxidase (GPx3) activity, total antioxidant capacity (TAC), 8-epi PGF2α and oxidized LDL were evaluated at the beginning and in the end of each intervention.

    Results: GBN intake significantly increased plasma Se from 87.0 ± 16.8 to 180.6 ± 67.1 μg/L, increased GPx3 activity in 24,8 % (from 112.66 ± 40.09 to 128.32 ± 38.31 nmol/min/mL, p < 0,05), and reduced 3.25 % of oxidized-LDL levels (from 66.31 ± 23.59 to 60.68 ± 20.88 U/L, p < 0.05). An inverse association between GPx3 and oxidized LDL levels was observed after supplementation with GBN by simple model (β -0.232, p = 0.032) and after adjustment for gender, age, diabetes and BMI (β -0.298, p = 0.008). There wasn’t association between GPx3 and 8-epi PGF2α (β -0.209, p = 0.052) by simple model. Conclusion: The partially defatted GBN intake has a potential benefit to increase plasma selenium, increase enzymatic antioxidant activity of GPx3 and to reduction oxidation in LDL in hypertensive and dyslipidemic patients. Be well! JP

  6. JP Says:

    Update 06/05/15:


    Eur J Nutr. 2015 Jan 8.

    Effects of Brazil nut consumption on selenium status and cognitive performance in older adults with mild cognitive impairment: a randomized controlled pilot trial.

    PURPOSE: Oxidative stress is closely related to cognitive impairment, and the antioxidant system may be a potential therapeutic target to preserve cognitive function in older adults. Selenium plays an important antioxidant role through selenoproteins. This controlled trial aimed to investigate the antioxidant and cognitive effects of the consumption of Brazil nuts, the best selenium food source.

    METHODS: We enrolled 31 older adults with mild cognitive impairment (MCI) who were randomly assigned to ingestion of Brazil nuts or to the control group. Participants of the treatment group consumed one Brazil nut daily (estimated 288.75 µg/day) for 6 months. Blood selenium concentrations, erythrocyte glutathione peroxidase (GPx) activity, oxygen radical absorbance capacity, and malondialdehyde were evaluated. Cognitive functions were assessed with the CERAD neuropsychological battery.

    RESULTS: Eleven participants of the treated group and nine of the control group completed the trial. The mean age of the participants was 77.7 (±5.3) years, 70 % of whom were female. We observed increased selenium levels after the intervention, whereas the control group presented no change. Among the parameters related to the antioxidant system, only erythrocyte GPx activity change was significantly different between the groups (p = 0.006). After 6 months, improvements in verbal fluency (p = 0.007) and constructional praxis (p = 0.031) were significantly greater on the supplemented group when compared with the control group.

    CONCLUSION: Our results suggest that the intake of Brazil nut restores selenium deficiency and provides preliminary evidence that Brazil nut consumption can have positive effects on some cognitive functions of older adults with MCI.

    Be well!


  7. JP Says:

    Updated 08/20/15:


    J Nutr. 2015 Aug 12.

    Dietary Almonds Increase Serum HDL Cholesterol in Coronary Artery Disease Patients in a Randomized Controlled Trial.

    BACKGROUND: More than one-half of coronary artery disease (CAD) patients have low HDL cholesterol despite having well-managed LDL cholesterol. Almond supplementation has not been shown to elevate circulating HDL cholesterol concentrations in clinical trials, perhaps because the baseline HDL cholesterol of trial subjects was not low.

    OBJECTIVE: This clinical trial was designed to test the effect of almond supplementation on low HDL cholesterol in CAD patients.

    METHODS: A total of 150 CAD patients (50 per group), with serum LDL cholesterol ≤100 mg/dL and HDL cholesterol ≤40 mg/dL in men and ≤50 mg/dL in women, were recruited from the Aga Khan University Hospital. After recording vital signs and completing a dietary and physical activity questionnaire, patients were randomly assigned to 1 of the following 3 groups: the no-intervention group (NI), the Pakistani almonds group (PA), and the American almonds group (AA). The respective almond varieties (10 g/d) were given to patients with instructions to soak them overnight, remove the skin, and eat them before breakfast. Blood samples for lipid profiling, body weight, and blood pressure were collected, and assessment of dietary patterns was done at baseline, week 6, and week 12.

    RESULTS: Almonds significantly increased HDL cholesterol. At weeks 6 and 12, HDL cholesterol was 12-14% and 14-16% higher, respectively, in the PA and AA than their respective baselines. In line with previous reports, serum concentrations of total cholesterol, triglycerides, LDL cholesterol, and VLDL cholesterol; total-to-HDL and LDL-to-HDL cholesterol ratios, and atherogenic index were reduced in both the PA and AA at weeks 6 and 12 compared with baseline (P < 0.05). Effect on serum lipids did not differ between the 2 almond groups. Dietary patterns, body weight, and blood pressure did not change in any of the 3 groups during the trial. CONCLUSION: A low dose of almonds (10 g/d) consumed before breakfast can increase HDL cholesterol, in addition to improving other markers of lipid abnormality in CAD patients with low starting HDL cholesterol. Be well! JP

  8. JP Says:

    Updated 02/19/17:


    Int J Endocrinol Metab. 2016 Jul 24;14(3):e34889.

    The Effect of Walnut Oil Consumption on Blood Sugar in Patients With Diabetes Mellitus Type 2.

    BACKGROUND: Prevalence of diabetes mellitus type 2 (DM) is increasing globally. Considering the potential role of poly-unsaturated fatty acids in prevention of DM type 2 and lipid profiles improvement, some studies have been carried out on walnut. However, there are no studies on control of blood sugar in DM type 2 patients using walnut.

    OBJECTIVES: The current study aimed to evaluate the effect of walnut oil on blood sugar in DM type 2 patients.

    METHODS: This randomized control clinical trial was performed on 100 patients with DM type 2. For the experiment group (n = 50), walnut oil (15 g/day for three months) was added to their diet, while the control group (n = 50) did not undergo any interventions. Before initiation of the experiment and after the experiment, the systolic and diastolic blood pressure (SBP and DBP) levels, fasting blood sugar (FBS) and HbA1c were measured.

    RESULTS: The two groups were not significantly different for SBP, DBP, body weight, and Body Mass Index. HbA1c level decreased significantly in the experiment group by 7.86% ± 21.97 (P = 0.005) from 7.00 ± 1.08 before the intervention to 6.37 ± 1.29 after the intervention. Also, FBS level decreased significantly by 8.24% ± 16.77 (P = 0.001); from 158.37 ± 48.16 before the intervention to 137.91 ± 23.24 after the intervention in the experimental group. These changes in the control group were not significant.

    CONCLUSIONS: Consumption of walnut oil (15 g/day for three months) was shown to improve blood glucose level but, no changes were noted for bodyweight and blood pressure in type two diabetic patients.

    Be well!


  9. JP Says:

    Updated 04/11/17:


    Nutr Diabetes. 2017 Apr 10;7(4):e259.

    Effects of walnut oil on lipid profiles in hyperlipidemic type 2 diabetic patients: a randomized, double-blind, placebo-controlled trial.

    BACKGROUND: The role of herbal medicine is now well documented in preventing and controlling diabetes mellitus. The main aim of this study was to evaluate the effects of walnut oil consumption on lipid profiles of hyperlipidemic patients with type 2 diabetes.

    METHODS: In a randomized, double-blind, placebo-controlled clinical trial, 100 hyperlipidemic type 2 diabetic patients aged 35-75 years were assigned to receive 15 cc Persian walnut oil or placebo every day for 90 days. The primary outcomes were the lipid profiles.

    RESULTS: Consumption of walnut oil by type 2 hyperlipidemic diabetic patients resulted in a significant decrease in total cholesterol levels (treatment difference (TD)=-30.04, P<0.001), triglyceride (TG) level (TD=-15.04, P=0.021), low-density lipoprotein (LDL) level (TD=-30.44, P<0.001) and total cholesterol to high-density lipoprotein (HDL) ratio (TD=-0.72, P<0.001) compared to the control group. There was a trend toward increasing HDL level with consumption of walnut oil (TD=2.28, P=0.06). Frequency of patients reaching a LDL level below 100 was higher in the case group (20 vs 0%).

    CONCLUSIONS: Addition of walnut oil in the daily diet of type 2 diabetic patients improves lipid profiles. Thus, it may be associated with a coronary artery disease risk factor modulation. Also, walnut oil may serve as a helpful natural remedy for hyperlipidemic patients with type 2 diabetes.

    Be well!


  10. JP Says:

    Updated 09/02/18:


    Indian Heart J. 2018 Jul – Aug;70(4):497-501.

    Acute effects of diets rich in almonds and walnuts on endothelial function.

    OBJECTIVE: Omega-3 fatty acids, especially alpha-linolenic acid (ALA), which are present in nuts may reduce cardiovascular disease (CVD) risk, by changing vascular inflammation and improving endothelial dysfunction. The objective of the study was to evaluate the acute effects of two different diets, one containing walnuts and the other almonds on endothelial function.

    METHODS: Twenty-seven overweight volunteers underwent a randomized 2-period, crossover, controlled intervention study. The subjects were given either walnut or almond diets which varied in monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) content. The walnut diet provided 23.1% energy from PUFA and the almond diet provided 7.6% energy from PUFA. Endothelial function was assessed physiologically by flow-mediated dilation (FMD) and biochemically by sVCAM (soluble vascular cell adhesion molecules).

    RESULTS: The walnut diet significantly improved FMD (p=0.004) and decreased sVCAM (p=0.009) whereas the almond diet tended to improve FMD (p=0.06) and significantly decreased sVCAM (p=0.004).

    CONCLUSION: Both walnut and almond diets improved FMD and sVCAM and there was no significant difference in physiological and biochemical markers between the two diets.

    Be well!


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