Nut intake lowers the risk of cardiovascular disease
In a study published yesterday in the American Journal of Clinical Nutrition, researchers performed a systematic review and meta-analysis of controlled trials to investigate the effects of tree nuts (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts) on blood lipids, lipoproteins, blood pressure and inflammation in adults 18 years and older without prevalent cardiovascular disease (CVD). Tree nut consumption was shown to lower total cholesterol, triglycerides, LDL cholesterol and its primary apolipoprotein, ApoB.
Of the 1,301 potentially eligible studies, 61 crossover and parallel trials met eligibility criteria with a total of 2,582 individuals. Interventions ranged from 3-26 weeks (median 4 weeks). Nuts were provided in all of the trials, rather than relying only on dietary advice. The amount of nuts varied from 5 to 100 grams per day (median 56 grams/day or approximately 2 ounces). Compared with the control groups, consumption of tree nuts (per serving/day) significantly lowered total cholesterol (-4.7mg/dL; 95% CI-5.3,-4.0), LDL cholesterol, ApoB (-3.7mg/dL; 95% CI -5.2,-2.3) and triglycerides (-2.2mg/dL; 95% CI-3.8,-0.5).
"Accumulating evidence suggests that nut intake lowers the risk of cardiovascular disease. Our findings, showing that nut intake lowers LDL cholesterol, ApoB and triglycerides in clinical trials, provide mechanistic evidence to support this relationship," said lead author Liana Del Gobbo, PhD, currently a researcher in Cardiovascular Medicine at Stanford University. She conducted the study as a research fellow at the Friedman School of Nutrition Science and Policy at Tufts. Interestingly, stronger effects for ApoB were observed in populations with type-2 diabetes (-11.5mg/dL; 95% CI-16.2,-6.8) than among healthy populations (-2.5mg/dL; 95% CI-4.7,-0.3) (p-heterogeneity=0.015). According to the senior author, Dariush Mozaffarian, MD, DrPH, Dean of the Friedman School of Nutrition Science and Policy at Tufts University, "ApoB can provide even better information about risk of heart disease than LDL concentrations. Our new findings suggest that eating nuts may be especially important for lowering cardiovascular risk in the setting of diabetes or insulin resistance."
Nuts contain important nutrients such as unsaturated fats, high quality protein, vitamins (i.e., vitamin E, folate and niacin), minerals (i.e., magnesium, calcium and potassium) and phytochemicals--all of which may offer cardioprotective properties, prompting the U.S. Food and Drug Administration to announce a qualified health claim for nuts and heart disease in 2003. The claim states, "Scientific evidence suggests, but does not prove, that eating 1.5 ounces per day of most nuts, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease."
"This new analysis provides further support that nuts can and should be part of a heart-healthy diet," states Maureen Ternus, M.S., R.D., Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF). "Just 1.5 ounces of nuts per day (about 1/3 cup) can provide many of the important vitamins, minerals and energy we need throughout the day."
Frequent nut consumption associated with less inflammation
In a study of more than 5,000 people, investigators from Brigham and Women's Hospital have found that greater intake of nuts was associated with lower levels of biomarkers of inflammation, a finding that may help explain the health benefits of nuts. The results of the study appear July 27 in the American Journal of Clinical Nutrition.
"Population studies have consistently supported a protective role of nuts against cardiometabolic disorders such as cardiovascular disease and type 2 diabetes, and we know that inflammation is a key process in the development of these diseases," said corresponding author Ying Bao, MD, ScD, an epidemiologist in BWH's Channing Division of Network Medicine. "Our new work suggests that nuts may exert their beneficial effects in part by reducing systemic inflammation."
Previously Bao and her colleagues observed an association between increased nut consumption and reduced risk of major chronic diseases and even death, but few prospective cohort studies had examined the link between nut intake and inflammation. In the current study, the research team performed a cross-sectional analysis of data from the Nurses' Health Study, which includes more than 120,000 female registered nurses, and from the Health Professionals Follow-Up Study, which includes more than 50,000 male health professionals. The team assessed diet using questionnaires and looked at the levels of certain telltale proteins known as biomarkers in blood samples collected from the study participants. They measured three well-established biomarkers of inflammation: C-reactive protein (CRP), interleukin 6 (IL6) and tumor necrosis factor receptor 2 (TNFR2).
After adjusting for age, medical history, lifestyle and other variables, they found that participants who had consumed five or more servings of nuts per week had lower levels of CRP and IL6 than those who never or almost never ate nuts. In addition, people who substituted three servings per week of nuts in place of red meat, processed meat, eggs or refined grains had significantly lower levels of CRP and IL6.
Peanuts and tree nuts contain a number of healthful components including magnesium, fiber, L-arginine, antioxidants and unsaturated fatty acids such as α-linolenic acid. Researchers have not yet determined which of these components, or if the combination of all of them, may offer protection against inflammation, but Bao and her colleagues are interested in exploring this further through clinical trials that would regulate and monitor diet.
"Much remains unknown about how our diet influences inflammation and, in turn, our risk of disease," said Bao. "But our study supports an overall healthful role for nuts in the diet and suggests reducing inflammation as a potential mechanism that may help explain the benefits of nuts on cardiometabolic diseases."
Nut consumption associated with reduced risk of some types of cancer
Cancer and type 2 diabetes are two of the most significant public health burdens facing the world today, and currently available data suggests their prevalence is expected to continue to increase. Nut consumption has long been hypothesized to have a role in preventing both of these diseases, but until now evidence has been inconsistent. A new systematic review and meta-analysis published in Nutrition Reviews on June 16, 2015 shows that nut consumption is, indeed, associated with a decreased risk of certain types of cancer, but not type 2 diabetes.
Researchers at the Mayo Clinic in Rochester, Minnesota, and the University of Minnesota in Minneapolis, Minnesota conducted a systematic review and meta-analysis of 36 observational studies (which included 30,708 patients) on the disease-preventive powers of nut consumption to create a comprehensive analysis. Upon completion, the authors concluded: "nut consumption was inversely associated with risk of colorectal cancer, endometrial cancer, and pancreatic cancer, but not with other types of cancer or type 2 diabetes. Overall, nut intake was associated with a decreased risk of cancer."
While many studies have evaluated the disease-preventive powers of nuts, the authors emphasize there is still a scarcity of available data on the relationship between individual types of cancer and nut consumption. Additional studies are consequently needed to more accurately assess these relationships.
"This is the first systematic review and meta-analysis study estimating the association between nut intake and risk of cancers. Our study suggests that nut consumption may be associated with reduced risk of cancers, which may have practical implication. Aligning with the known beneficial effect of nuts on heart diseases, our study may imply that individuals interested in making better food choices to reduce the risk of cancer and heart disease can consider consuming nuts, after considering the caloric and fat contents of different types of nuts", said Lang Wu, the lead author of this study.
Nuts and peanuts -- but not peanut butter -- linked to lower mortality rates
A paper published in the International Journal of Epidemiology confirms a link between peanut and nut intake and lower mortality rates, but finds no protective effect for peanut butter. Men and women who eat at least 10 grams of nuts or peanuts per day have a lower risk of dying from several major causes of death than people who don't consume nuts or peanuts.The reduction in mortality was strongest for respiratory disease, neurodegenerative disease, and diabetes, followed by cancer and cardiovascular diseases. The effects are equal in men and women. Peanuts show at least as strong reductions in mortality as tree nuts, but peanut butter is not associated with lower mortality, researchers from Maastricht University found.
This study was carried out within the Netherlands Cohort Study, which has been running since 1986 among over 120,000 Dutch 55-69 year old men and women. Nut consumption was assessed by asking about portion size and frequency of intake of peanuts, other nuts (tree nuts), and peanut butter. The researchers from Maastricht University analyzed the relationship with overall and cause-specific mortality since 1986.
The associations between nuts and peanut intake and cardiovascular death confirm earlier results from American and Asian studies that were often focused on cardiovascular diseases. However, in this new study, it was found that mortality due to cancer, diabetes, respiratory, and neurodegenerative diseases was also lowered among users of peanuts and nuts. Project leader and epidemiologist
Professor Piet van den Brandt commented:
"It was remarkable that substantially lower mortality was already observed at consumption levels of 15 grams of nuts or peanuts on average per day (half a handful). A higher intake was not associated with further reduction in mortality risk. This was also supported by a meta-analysis of previously published studies together with the Netherlands Cohort Study, in which cancer and respiratory mortality showed this same dose-response pattern."
Peanuts and tree nuts both contain various compounds such as monounsaturated and polyunsaturated fatty acids, various vitamins, fiber, antioxidants, and other bioactive compounds, that possibly contribute to the lower death rates. In contrast to peanuts, no association was found between peanut butter intake and mortality risk. However, besides peanuts, peanut butter contains also added components like salt and vegetable oils. In the past, it has been shown that peanut butter contains trans fatty acids and therefore the composition of peanut butter is different from peanuts. The adverse health effects of salt and trans fatty acids could inhibit the protective effects of peanuts.
Peanut consumption decreases mortality
If you're looking for a simple way to lower your risk of dying from a heart attack, consider going nuts.
Researchers at Vanderbilt University and the Shanghai Cancer Institute examined the association of nut consumption with mortality among low-income and racially diverse populations and found that intake of peanuts was associated with fewer deaths, especially from heart disease.
The study was published March 2, 2015 in JAMA Internal Medicine. The first author of the paper is Hung Luu, Ph.D., a post-doctoral fellow in the Division of Epidemiology, Vanderbilt University Medical Center. Senior author is Xiao-Ou Shu, M.D., Ph.D., associate director for Global Health at the Vanderbilt-Ingram Cancer Center and professor of Medicine in the Department of Epidemiology.
"Nuts are rich in nutrients, such as unsaturated fatty acids, fiber, vitamins, phenolic antioxidants, arginine and other phytochemicals. All of them are known to be beneficial to cardiovascular health, probably through their anti-oxidative, anti-inflammatory and endothelial function maintenance properties," Shu said.
While research has previously linked nut consumption with lower mortality, those studies focused mainly on higher-income, white populations. This study was the first to discover that all races - blacks, whites, and Asians alike - could potentially increase heart health by eating nuts and peanuts.
"In our study, we found that peanut consumption was associated with reduced total mortality and cardiovascular disease mortality in a predominantly low-income black and white population in the U.S., and among Chinese men and women living in Shanghai," Shu said.
This study was based on three large on-going cohort studies. Participants included over 70,000 Americans of African and European descent from the Southern Community Cohort Study (SCCS), who were mostly low-income, and over 130,000 Chinese from the Shanghai Women's Health Study (SWHS) and the Shanghai Men's Health Study (SMHS).
Information on nut consumption was collected by structured questionnaires at the baseline survey. For participants in the SCCS, deaths were determined by linking with the National Death Index and Social Security Administration mortality files, and for participants in the SWHS/SMHS, by linking with the Shanghai Vital Statistics Registry and by conducting home visits. In total, over 14,000 deaths were identified, with a median follow-up of 5.4 years in the SCCS, 6.5 years in the SMHS, and 12.2 years in the SWHS.
Peanut consumption was associated with decreased total mortality, particularly cardiovascular mortality (i.e., 17 percent-21 percent reduction in total mortality, and 23 percent-38 percent reduction in cardiovascular mortality for the highest quartile intake group compared to the lowest quartile group) across all three racial/ethnic groups, among both men and women, and among individuals from low-SES groups.
Because peanuts are much less expensive than tree nuts, as well as more widely available to people of all races and all socioeconomic backgrounds, increasing peanut consumption may provide a potentially cost-efficient approach to improving cardiovascular health, Shu said.
"The data arise from observational epidemiologic studies, and not randomized clinical trials, and thus we cannot be sure that peanuts per se were responsible for the reduced mortality observed," said William Blot, Ph.D., associate director for Cancer Prevention, Control and Population-based Research at VICC and a co-author of the study.
He did note that "the findings from this new study, however, reinforce earlier research suggesting health benefits from eating nuts, and thus are quite encouraging."
Consumption of peanuts with a meal benefits vascular health
A study of peanut consumption showed that including them as a part of a high fat meal improved the post-meal triglyceride response and preserved endothelial function.
"Peanuts are a healthy snack when eaten as part of a healthy diet," said lead researcher Xiaoran Liu, a graduate student in the Department of Nutritional Sciences at The Pennsylvania State University.
The purpose of this research was to evaluate vascular function after a high fat meal challenge. Overweight males (n = 15) were randomized to either a peanut meal containing 3 oz. of ground peanuts (as a shake) or a control meal (a shake without peanuts) that were matched for energy and macronutrients.
The lipid profile, glucose and insulin were measured five times after each meal. Flow-mediated dilatation (FMD) was measured to assess vascular function. This non-invasive method required a cuff at the forearm to restrain blood flow, which was then released to assess dilation of the brachial artery. The control meal decreased FMD by 1.2% compared to baseline.
In contrast, there was no decrease in FMD after the peanut meal. These results demonstrate that the peanut meal maintained normal vascular function whereas the high fat-matched control meal impaired vascular function acutely. Vascular dysfunction plays a major role in the development of atherosclerosis and the formation of coronary plaques and lesions that lead to coronary artery disease. Typically after a high fat meal, vascular function is reduced, albeit temporarily, until the fat that is in the blood (from the meal) is cleared. Strategies that can blunt this response to both dietary fat and its effect on vascular dysfunction may decrease the risk of coronary disease. These findings demonstrated that that peanut consumption was shown to be atheroprotective as a part of high fat meal.
"Previous studies have shown that individuals who consume peanuts more than 2 times a week have a lower risk of coronary heart disease," said Liu. "This study indicates that the protective effect of peanut consumption could be due, in part, to its beneficial effect on artery health".
Peanuts are nutrient dense and energy dense, so Liu noted the importance of being aware of their calorie content when incorporating them in the diet. Thus, peanuts must replace other food sources of calories when included in the diet. For example, peanuts can be substituted for high fat, nutrient-poor foods in the diet that contain solid fats.
Looking ahead, the Penn State group hopes to investigate the effects of peanut consumption on other risk factors including inflammatory markers. Liu presented the research at the American Society for Nutrition's Scientific Sessions & Annual Meeting at EB 2015.
Tree nuts have a positive impact on metabolic syndrome criteria associated with mortality, a twofold increased risk for cardiovascular disease, and a fivefold increased risk for type 2 diabetes.
Two new (2014) meta-analyses involving tree nuts (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts) were recently published in the online publications, British Medical Journal Open (BMJ Open) (i) and PLOS ONE (ii).
The BMJ Open article looked at the effects of tree nuts on metabolic syndrome (MetS) criteria and showed that tree nut consumption resulted in a significant decrease in triglycerides and fasting blood glucose. The PLOS ONE article focused on the effect of tree nuts on glycemic control in diabetes and showed significant decreases in HbA1c and fasting blood glucose levels. Researchers from the University of Toronto conducted both meta-analyses.
In the paper focusing on MetS, the analysis included 47 randomized control trials with 2,200 participants who were otherwise healthy or had MetS criteria, dyslipidemia (elevated levels of blood choleterol and/or triglycerides), or type 2 diabetes.
"We found that tree nut consumption of about two ounces per day was found to decrease triglycerides significantly by ~0.06 mmol/L and to decrease fasting blood glucose significantly by ~0.08 mmol/L over an average follow-up of eight weeks," stated Cyril Kendall, Ph.D., lead researcher of the study.
This is important since MetS is a cluster of risk factors shown to be associated with mortality, a twofold increased risk for cardiovascular disease, and a fivefold increased risk for type 2 diabetes. While the diagnostic criteria can vary, presence of any three of the five following conditions results in a diagnosis of MetS: abdominal obesity, elevated triglycerides, low HDL cholesterol (the good cholesterol), high blood pressure, and hyperglycemia (high blood sugar levels). Based on NHANES data from 2003-2006, an estimated 34.3% of the U.S. population has MetS.
In addition to the effect of nuts on MetS, the researchers also looked at the effect of nuts on glycemic control in those with diabetes.
The PLOS ONE analysis included 12 randomized clinical trials with 450 participants and compared the effects of diets emphasizing tree nuts to isocaloric diets without tree nuts on HbA1c (a marker of longer term blood sugar control), fasting blood glucose, fasting insulin and insulin resistance (HOMA-1R). The results showed that diets emphasizing about two ounces of tree nuts per day significantly lowered HbA1c (P=0.0003) and fasting glucose (P=0.03) compared to the control diets. While neither diet showed significant effects on fasting insulin and insulin resistance, the direction of effect favored tree nuts.
According to Dr. Kendall, "Both of our analyses indicate that daily tree nut consumption has an overall metabolic benefit and can improve risk factors for metabolic syndrome, and glycemic control in individuals with type 2 diabetes."
"With MetS and diabetes on the rise worldwide, this is yet another reason to include tree nuts in your diet every day," states Maureen Ternus, M.S., R.D., Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF). "In 2003, FDA (in its qualified health claim for nuts and heart disease) recommended that people eat 1.5 ounces of nuts per day—well above current consumption levels. We need to encourage people—especially those at risk for MetS and those with diabetes—to get their handful of nuts every day."
Nut consumption = reduced death rate
In a study published November 20, 2013 in the New England Journal of Medicine, researchers looked at the association of nut consumption with total and cause-specific mortality among 76,464 women in the Nurses' Health Study and 42,498 men in the Health Professionals Follow-up Study. Consumption of nuts, including tree nuts (such as almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts), was inversely associated with total mortality in both men and women, independent of other predictors for death. In addition, there were significant inverse associations for deaths due to cancer, heart disease and respiratory disease.
"Compared with those who did not eat nuts, individuals who consumed nuts (serving size of one ounce) seven or more times per week had a 20% lower death rate and this association was dose-dependent," stated lead author, Ying Bao, MD, ScD, from the Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA. "Those who consumed more nuts were also leaner, and tended to have a healthy lifestyle, such as smoking less and exercising more," added Dr. Bao.
This is the largest study to date to examine the relation between nut consumption and total mortality, and the results are consistent with previous studies, according to senior author, Charles Fuchs, MD, MPH, from the Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA. "The findings from our study and others suggest a potential benefit of nut consumption for promoting health and longevity," reported Dr. Fuchs.
Nuts contain important nutrients such as unsaturated fats, high quality protein, vitamins (i.e., vitamin E, folate and niacin) minerals (i.e., magnesium, calcium and potassium) and phytochemicals—all of which may offer cardioprotective, anticarcinogenic, anti-inflammatory and antioxidant properties. "With current nut consumption well below the recommended 1.5 ounces of nuts per day (in the FDA qualified health claim for nuts and heart disease) we need to continue to encourage people to have a handful of nuts every day," recommends Maureen Ternus, M.S., R.D., Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF).
In a large prospective study published online November 2013 in the British Journal of Cancer, researchers looked at the association between nut consumption and risk of pancreatic cancer among 75,680 women in the Nurses' Health Study, with no previous history of cancer. Consumption of nuts, including tree nuts (such as almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts), was inversely associated with risk of pancreatic cancer, independent of other potential risk factors for pancreatic cancer.
Women who consumed a one-ounce serving of nuts two or more times per week had a significantly reduced risk of pancreatic cancer (RR, 0.65; 95% CI, 0.47-0.92; P=0.007) compared to those who largely abstained from nuts. "This reduction in risk was independent of established or suspected risk factors for pancreatic cancer including age, height, obesity, physical activity, smoking, diabetes and dietary factors," stated lead author, Ying Bao, MD, ScD, from the Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
Pancreatic cancer is the fourth most common cause for cancer-related mortality in the U.S., yet very few modifiable risk factors have been identified. According to the 2009 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) report, aside from cigarette smoking, body fatness was the only convincing modifiable risk factor for pancreatic cancer.
While there may be concern that frequent nut consumption may result in weight gain and thereby increase the risk of developing pancreatic cancer, the opposite seems to be true. "In our cohort women who consumed the most nuts tended to weigh less," reported Dr. Bao. Moreover, in a recent analysis of this same cohort, higher nut consumption was associated with a slightly lower risk of weight gain and obesity.
Nut intake has also been associated with a reduced risk of diabetes mellitus, which is a risk factor for pancreatic cancer. "Nuts contain a variety of important vitamins, minerals and phytochemicals," states Maureen Ternus, M.S., R.D., Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF). "This exciting, new study provides yet another reason to encourage people to eat a handful—or 1/3 cup—of tree nuts every day."
New findings on tree nuts and health
Three new studies involving tree nuts (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts) were presented April 2013 at the Experimental Biology Meeting in Boston, MA. Tree nut consumption was associated with a better nutrient profile and diet quality; lower body weight and lower prevalence of metabolic syndrome; and a decrease in several cardiovascular risk factors compared to those seen among non-consumers.
First, the Adventist Health Study looked at the effect of nut intake on the risk of metabolic syndrome (MetS) in a population with a wide range of nut intake ranging from never to daily. Researchers at Loma Linda University studied 803 adults using a validated food frequency questionnaire and assessed both tree nut and peanut intake together and separately.
"Our results showed that one serving (28g or 1 ounce) of tree nuts per week was significantly associated with 7% less MetS," stated lead researcher Karen Jaceldo-Siegl, DrPH. "Interestingly, while overall nut consumption was associated with lower prevalence of MetS, tree nuts specifically appear to provide beneficial effects on MetS, independent of demographic, lifestyle and other dietary factors."
The second study looked at 14,386 adults participating in the 2005-2010 National Health and Nutrition Examination Surveys (NHANES). Intake was from 24-hour recall data and tree nut consumers were defined as those who consumed more than 1/2 ounce of tree nuts (average consumption was about an ounce/day).
As seen in previous research, tree nut consumers had higher daily intakes of calories (2468 v 2127 calories) and nutrients of concern: fiber (21v 16 grams [g]); potassium (3028 v 2691 milligrams [mg]); magnesium (408 v 292 mg); monounsaturated fats (36 v 29 g), and polyunsaturated fatty acids (21 v 17 g), but lower intakes of added sugars (15 v 18 teaspoons), saturated fats (25 v 27g), and sodium (3197 v 3570 mg) than non-consumers. Tree nut consumers also had lower weight (80 v 82 kg; p=0.0049), BMI (28v 29; p<0 .0001="" 98="" and="" circumference="" cm="" non-consumers.="" p="0.0006)" span="" than="" v="" waist="">0>
In addition, those who consumed tree nuts had lower systolic blood pressure (120 v 122 mmHg; p=0.0120) and higher HDL-cholesterol (the good kind) (55 v 53 mg/dL; p=0.0020).
On a population basis, these reduced risk factors could lead to better health.
"Consumption of tree nuts should be encouraged to improve diet quality, nutrient intake, weight status, and some cardiovascular risk factors," according to Carol O'Neil, PhD, MPH, RD, lead author on the paper and Professor at Louisiana State University Agricultural Center.
Finally, a third study looked at several markers for cardiovascular disease risk. In 2011, researchers from the University of Toronto and St. Michael's Hospital in Toronto, Canada, published the largest study to date on nuts and diabetes (Jenkins, D.J.A., et al., 2011. Nuts as a replacement for carbohydrates in the diabetic diet. Diabetes Care. 34(8):1706-11.), showing that approximately two ounces of nuts a day, as a replacement for carbohydrate foods, can improve glycemic control and blood lipids in those with type 2 diabetes. The researchers looked at the effects of nuts on various cardiovascular markers.
"We found that nut consumption was associated with an increase in monounsaturated fatty acids (the good fats) in the blood, which was correlated with a decrease in total cholesterol, LDL cholesterol (the bad kind), blood pressure, 10-year coronary heart disease risk, HbA1c (a marker of blood sugar control over the previous three months) and fasting blood glucose," explained Cyril Kendall, Ph.D., of the University of Toronto. "Nut consumption was also found to increase LDL particle size, which is less damaging when it comes to heart disease risk." According to Dr. Kendall, this study found additional ways in which nut consumption may improve overall cardiovascular health.
"These three new studies, independent of one another, support the growing body of evidence showing that consuming nuts can improve your health," states Maureen Ternus, M.S., R.D., Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF). "In 2003, FDA (in its qualified health claim for nuts and heart disease) recommended that people eat 1.5 ounces of nuts per day—well above current consumption levels—so we need to encourage people to grab a handful of nuts every day."
Tree Nut Consumption = Lower Body Weight & Fewer Health Risks
In a study published in the Journal of the American College of Nutrition, April 2012 researchers compared risk factors for heart disease, type 2 diabetes and metabolic syndrome of nut consumers versus those who did not consume nuts. Tree nut (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts) consumption specifically, was associated with higher levels of high-density lipoprotein-cholesterol (good cholesterol) and lower levels of C-reactive protein, a marker for inflammation which can lead to a variety of chronic diseases including heart disease.
“One of the more interesting findings was the fact that tree nut consumers had lower body weight, as well as lower body mass index (BMI) and waist circumference compared to nonconsumers. The mean weight, BMI, and waist circumference were 4.19 pounds, 0.9kg/m2 and 0.83 inches lower in consumers than non-consumers, respectively,” stated Carol O’Neil, PhD, MPH, RD, lead author on the paper and Professor at Louisiana State University Agricultural Center.
The study looked at 13,292 men and women (19+ years) participating in the 1999-2004 National Health and Nutrition Examination Surveys (NHANES).
Tree nut consumption was associated with a five percent lower prevalence of metabolic syndrome, a name for a group of risk factors that occur together and increase the risk for coronary artery disease, stroke and type 2 diabetes. In addition, tree nut consumers had a lower prevalence of four risk factors for metabolic syndrome: abdominal obesity, high blood pressure, high fasting glucose (blood sugar) levels and low high-density lipoprotein-cholesterol levels.
Moreover, previous research by the same authors, showed that although tree nut consumption in the U.S. population is relatively low (mean intake of 1.19 ounces/day for nut consumers) nutrient intakes and diet quality were significantly improved when tree nuts were consumed. The latter appear to be associated with a greater intake of whole grains, fruits, and less saturated fatty acid, sodium and calories from solid fats, alcohol and added sugars. As a result, Dr. O’Neil recommends, “Tree nuts should be an integral part of a healthy diet and encouraged by health professionals—especially registered dietitians.”
Consumers of OOHN, including tree nuts (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts), had higher intakes of energy, monounsaturated and polyunsaturated fats (the good fats) and dietary fiber, and lower intakes of carbohydrates, cholesterol and sodium than non-consumers.
“Adult consumers also had a 19% decreased risk of hypertension and a 21% decreased risk of low high-density lipoprotein (HDL--the good cholesterol) levels—both risk factors for metabolic syndrome and cardiovascular disease,” stated Carol O’Neil, PhD, MPH, RD, lead author on the paper and Professor at Louisiana State University Agricultural Center.
According to Dr. O’Neil, “We decided to look at OOHN specifically because this shows an individual’s conscious decision to consume nuts, which may be associated with a desire for a healthier lifestyle.” Interestingly, the percent of OOHN consumers increased with age: 2.1% ± 0.3%, 2.6% ± 0.3%, 6.5% ± 0.5%, and 9.6% ± 0.5% of those aged 2 to 11, 12 to 18, 19 to 50, and 51+ years, respectively. The two latter groups were combined into a single group of consumers aged 19+ years for subsequent analyses.
“In all of the age groups, although energy intake was higher in OOHN consumers than non-consumers, neither weight nor body mass index (BMI) was higher. This suggests that OOHN consumers are better able to balance energy intake with energy output than non-consumers,” stated Dr. O’Neil. This research comes on the heels of another study by the same authors, published in the Journal of the American College of Nutrition, which showed that tree nut consumers specifically (ages 19+) had lower body weight, as well as lower BMI and waist circumference compared to non-consumers. The mean weight, BMI, and waist circumference were 4.19 pounds, 0.9kg/m2 and 0.83 inches lower in consumers than non-consumers, respectively.
“These new data, along with previous research, show once again that nuts can and should play an important role in a healthy diet,” adds Maureen Ternus, M.S., R.D., Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF). “With current nut consumption well below the recommended 1.5 ounces of nuts per day (in the FDA qualified health claim for nuts and heart disease) people should be encouraged to grab a handful of nuts every day. Eat them as a snack or throw some on yogurt, salad or oatmeal.”
Tree nuts have the potential to help reduce the risk of coronary heart disease (CHD) in people with type 2 diabetes
Findings from a new study[i] published in Nutrition, Metabolism & Cardiovascular Diseases show that the fatty acids in nuts have the potential to help reduce the risk of coronary heart disease (CHD) in people with type 2 diabetes.
Researchers from the University of Toronto and St. Michael’s Hospital in Toronto, Canada, found that incorporating about two ounces of tree nuts (almonds, Brazils, cashews, hazelnuts, pecans, pine nuts, pistachios, macadamias and walnuts) and peanuts into the diet of people with diabetes, was inversely associated with CHD risk factors and 10-year CHD risk.
According to Cyril Kendall, Ph.D., co-investigator of the study, “While a number of studies have shown that nuts can help reduce the risk of CHD and diabetes, no research to date has looked at the how nuts alter the fatty acid profile in people with diabetes and how this relates to cardiovascular health.”
This study is a secondary analysis of the 2011 nuts and diabetes study[ii] by the same researchers. The original study was a 3-month parallel design with 117 non-insulin dependent adults with diabetes (men and women with a mean age of 62 years) who were all being treated with oral hypoglycemic medications. The subjects were randomized to one of three diets for three months. The first diet included a supplement of 75g (~2½ ounces or ½ cup) of mixed nuts; the second diet included 38g (~1⅓ ounces or ¼ cup) of mixed nuts and half portion of muffins; and the third diet contained a full portion of muffins. Each supplement provided approximately 475 calories per 2,000 calorie diet. All of the diets contained roughly the same number of calories but the nuts provided more unsaturated (i.e. healthy) fat and less carbohydrate.
“The results of our current study indicate that by incorporating nuts into a diabetes diet, one can modify the fatty acid profile of adults with type 2 diabetes by modestly increasing the unsaturated fatty acid content of blood lipids,” explained Dr. Kendall. “This in turn has the potential to contribute to the total reduction of CHD risk in those same individuals.”
Numerous studies have shown that consuming tree nuts may reduce the risk of heart disease. In 2003 tree nuts received a qualified health claim from the U.S. Food and Drug Administration (FDA) which states, “Scientific evidence suggests but does not prove that eating 1.5 ounces per day of most nuts, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.” Interestingly, individuals with Type 2 diabetes have a 2-4 fold higher risk of cardiovascular disease (CVD) compared with nondiabetic individuals of similar age, sex and ethnicity.
[i] Nishi, S.K., C.W.C. Kendall, R.P. Bazinet, B. Bashyam, C.A. Ireland, L.S.A. Augustin, S. Blanco Mejia, J.L. Sievenpiper, D.J.A. Jenkins. Nut consumption, serum fatty acid profile and estimated coronary heart disease risk in type 2 diabetes, Nutrition, Metabolism & Cardiovascular Diseases (2014), http://dx.doi.org/10.1016/j.numecd.2014.04.001
[ii] Jenkins, D.J.A., C.W.C. Kendall, M.S. Banach, K. Srichaikul, E. Vidgen, S. Mitchell, T. Parker, S. Nishi, B. Bashyam, R. de Souza, C. Ireland, R.G. Josse, 2011. Nuts as a replacement for carbohydrates in the diabetic diet. Diabetes Care. 34(8):1706-11.