Let’s Talk About Fat…
One of the first things most people say about pistachios is, “They’re fattening!” But what if you were to find out, this wasn’t necessarily true? We have some very good news for all our fellow pistachio lovers. So please, read on…
First of all, fat is essential to maintain the integrity of the cells in the body. Fats help the body absorb fat-soluble vitamins such as A, D, E and K, and provide a concentrated source of energy that is stored in cells for future use.
Many nutrition professionals recommend that no more than 35% of daily calories come from fat, most of which should be from the healthier, unsaturated fats.
So let’s look at the different types of fat…
SATURATED FATS are found primarily in beef and dairy products. Diets high in saturated fat tend to raise both total cholesterol and LDL* (the bad) cholesterol levels, which is associated with an increased risk of heart disease. Saturated fat should be limited to less than 10% of daily calories.
TRANS FATS are found in processed foods made with partially hydrogenated vegetable oils. Like saturated fats, trans fats raise the LDL cholesterol level that increases the risk of heart disease.
POLYUNSATURATED FATS are usually a good source of essential fat, like linoleic and linolenic acids that are needed by cells, but cannot be made by the body. Polyunsaturated fats in the diet have been shown to lower total cholesterol and LDL cholesterol levels, but also lower HDL* (the good) cholesterol. Polyunsaturated fats are found in nuts and vegetable oils, and should make up 10% or less of daily calories.
MONOUNSATURATED FATS, the predominant fat found in pistachios, other nuts and olive oil, have been shown to lower total cholesterol and LDL cholesterol levels while maintaining the beneficial HDL cholesterol level associated with lowering the risk of heart disease. Up to 20% of daily calories can come from monounsaturated fat.
But Now for Some Really Great News…
In July 2003, the FDA approved a qualified health claim for pistachios: "Scientific evidence suggests but does not prove that eating 1.5 oz. per day of most nuts, such as pistachios, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease."
The Relationship Between Fat and Cholesterol…
In a healthy diet, fat provides flavor, satiety, and helps the body absorb fat-soluble vitamins. Fat is needed to maintain healthy skin and hair, protect cell walls, keep bodies warm and protect organs. Cutting fat intake too low may actually pose a health risk.
Cholesterol is produced in the body, and is also derived from foods of animal origin such as meat, poultry, seafood and dairy products. Food from plant sources such as fruits, vegetables, nuts and seeds do not contain cholesterol. The body needs cholesterol to enable certain minerals and water to pass from the bloodstream into and out of the body’s cells. In fact, cholesterol is so important that the liver creates it even if it’s not consumed in the diet.
Because cholesterol doesn’t dissolve in the blood, two major types of lipoproteins (compounds composed of fat and protein) carry it through the bloodstream. One is low-density lipoprotein, known as LDL cholesterol. LDL cholesterol is considered “bad” because a high level can raise the risk of cardiovascular diseases, including heart attack and stroke. The second type of lipoprotein is high-density lipoprotein, or HDL cholesterol, which is considered “good” because high levels of HDL cholesterol appear to protect against heart disease.
Dietary intake of fat seems to affect cholesterol levels to a great degree. Research shows that diets high in saturated fat raise both total and LDL cholesterol levels. The higher the cholesterol levels, the greater the risk of heart disease America’s number one killer. Replacing dietary intake of cholesterol-raising (saturated fat) foods with cholesterol-lowering (unsaturated fat) foods will lead to better health. Several studies have shown that monounsaturated fat found in pistachios can help decrease both total and LDL cholesterol levels. In fact, findings from a Loma Linda University study revealed that people who ate nuts five or more times per week were half as likely to have a heart attack or die of heart disease as people who rarely or never ate nuts.
The Role of Pistachios in Heart Health…
Coronary heart disease remains the leading cause of death, accounting for almost 40% of all deaths in the United States. And, heart disease is not just a man's disease it's also the #1 killer of women. High cholesterol, a major risk factor associated with heart disease, affects nearly 100 million adults. Lowering high cholesterol through a healthy diet and exercise can significantly lower heart disease risk (1).
While it is well accepted that diets high in saturated fats are linked to increased incidence of heart disease, more recent evidence shows a link between monounsaturated fatty acids and decreased heart disease risk. Research studies specifically with nuts, including pistachios, that contain relatively high amounts of monounsaturated fatty acids, show similar results in reducing risk factors associated with heart disease. When the U.S. Food and Drug Administration (FDA) announced the first qualified health claim for nuts in July 2003 it quickly elevated the status of research on nuts and monounsaturated fats even further, acknowledging that eating nuts can play a role in lowering coronary heart disease risk. The claim states, "Scientific evidence suggests but does not prove that eating 1.5 ounces per day of most nuts, such as pistachios, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease" (2).
Over 30 research studies have shown that including nuts in the diet can reduce the risk of heart disease (3). Epidemiological evidence from major population studies, which began with observations in Seventh Day Adventists (4), has documented the association between frequent nut consumption and lowered coronary heart disease risk. In the Nurses' Health Study (5), frequent nut consumption (greater than five times per week) significantly reduced heart disease risk. Clinical research trials on consumption of each of the specific nuts pistachios, almonds, walnuts, peanuts, hazelnuts, pecans and macadamias show significant decreases in both total and LDL cholesterol levels. Results of a meta-analysis of these clinical nut research studies (6) reveal:
- Subjects with normal or high cholesterol levels can achieve significant total and LDL cholesterol lowering.
- Dietary regimens with increased monounsaturated fats from nuts can be based on low fat recommendations (30% calories from fat) or a more traditional American diet (35-39% calories from fat) and show significant lowering of total and LDL cholesterol levels.
- The percentage of monounsaturated fat (15-25% of calories) necessary to demonstrate results can be obtained by including 41-103 grams (2-3.5 ounces) of specified nuts within the daily diet.
- Overall, nuts can significantly lower total cholesterol by 4.5% and LDL cholesterol by 6.7% when an average of 71.3 grams per day of nuts was consumed. In subjects with elevated cholesterol levels, nuts lowered total cholesterol by 4.6% and LDL cholesterol by 8.5%.
- Nuts lowered triglycerides in subjects with elevated triglycerides at baseline by 8.4%.
- Based on reductions in LDL cholesterol alone, nuts may reduce the risk of heart disease by 5-12%.
Recently revised dietary recommendations in the U.S. from the American Heart Association (7), U.S. Department of Health and Human Services "Healthy People 2010" (8) and the National Institutes of Health's National Cholesterol Education Program Adult Treatment Panel III Report (9) emphasize unsaturated fat intake and moderate, not low, fat diets in the prevention of coronary heart disease. These reports show a change from dietary guidance that previously recommended lowering total fat to 30% or less of calories and monounsaturated fat to 10% or less of calories. The Third Report of the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults, released by the National Cholesterol Education Program, formalizes the recommendation to keep total fat in the diet to between 25-35% of calories and consume monounsaturated fat up to 20% of calories (9). The American Heart Association recommends up to 20% of calories from monounsaturated fat and substituting unsaturated fat from vegetables, fish, legumes and nuts (7).
The National Academy of Sciences' (NAS) Institute of Medicine issued an updated report "Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Protein and Amino Acids" or the "Macronutrient report" (10) establishing dietary fat goals at a wider range, from 20% up to 35% of calories, or from low to moderate amounts of fat for a healthy diet. While there were no specific values set for monounsaturated fat, the NAS report does recommend switching from saturates to monounsaturates and polyunsaturates. In the meantime, the NAS report set values for essential fatty acids linoleic and linolenic acids. Pistachios contain 3.87 grams of omega-3 fatty acid, linoleic acid, per one-ounce serving. That is 22% of the 17 grams/day NAS set for men and 32% of 12 grams/day NAS set for women.
Building a heart-healthy diet can be easy by substituting nuts, such as pistachios, for some of the calories and saturated fat you usually consume. Pistachios contain predominantly monounsaturated fat and can fit well within a heart-healthy diet that includes up to 35% of calories from total fat and 20% of calories from monounsaturated fat (12). Pistachios contain 1.5 grams of saturated fat per one-ounce serving and are cholesterol free. As complex plant foods, nuts contain many bioactive compounds that may also play a protective cardiovascular role. Pistachios contain significant amounts of magnesium, copper and potassium, and contain a high level of beta-sitosterol, (13) which is one of several plant sterols implicated in cholesterol lowering (11). Pistachios are a good source of dietary fiber (with over 10% of the Daily Value in a one-ounce serving), and are relatively high in the amino acid arginine, which appears to maintain flexible arteries and enhance blood flow by boosting nitric oxide, a compound that relaxes blood vessels (11).
Finally, antioxidant capability has been measured in pistachios, (14) as well as significant amounts of compounds like lutein (13) and two anthocyanins (cyanidin 3-galactoside and cyanidin 3-glucoside) (15) have been detected that warrant further study.
1. American Heart Association Heart Disease and Stroke Statistics
2. FDA Office of Nutritional Products, Labeling and Dietary Supplements, Center for Food Safety and Applied Nutrition (July 2003) "Qualified Health Claims: Letter of Enforcement Discretion - Nuts and Coronary Heart Disease (Docket No 02P-0505)" http://www.cfsan.fda.gov/~dms/qhcnuts2.html
3. International Tree Nut Council's Nutrition Research and Education Foundation http://www.nuthealth.org/nutrition.php3?action=reference#1b
4. G.E. Fraser, J. Sabate, W.L. Beeson, T.M. Strahan (1992) "A possible protective effect of nut consumption on risk of coronary heart disease: The Adventist Health Study." Arch Intern Med 152:1416-1424.
5. F.B. Hu, M.J. Stampfer (1999) "Nut consumption and risk of coronary heart disease: a review of epidemiological evidence." Current Atherosclerosis Reports 1:204-209.
6. V. Fulgoni, M. Abbey, C. Alper, P. Davis, I. Durak, C. Kendall, M. Most, D. O'Byrne, G. Spiller (2003) "Eating nuts lowers total and LDL cholesterol: Results of a meta-analysis of human feeding studies."
7. R.M. Krauss et al (2000) "AHA Dietary Guidelines: Revision 2000: A Statement for Healthcare Professionals from the Nutrition Committee of the American Heart Association." Circulation 102:2284-2299.
8. U.S. Department of Health and Human Services: Healthy People 2010: Understanding and Improving Health, Second Edition, Washington DC; U.S. Government Printing Office; November 2000.
9. Expert Panel on Detection, Evaluation and Treatment of High Cholesterol in Adults (2001) "Executive summary of the third report of the National Cholesterol Education Program expert panel on detection, evaluation & treatment of high blood cholesterol in adults (adult treatment panel III)." JAMA 285:2486-2497.
10. National Academy of Sciences' Institute of Medicine (2002) "Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Protein and Amino Acids."
11. P.M. Kris-Etherton, G. Zhao, A.E. Binkoski, S.M. Coval, T. Etherton (2001) "The effects of nuts on coronary heart disease risk." Nutr Rev 59:103-111.
12. California Pistachio Commission http://www.pistachios.org/healthnut
13. USDA Nutrient Database for Standard Reference, Release 16 (July 2003) http://www.nal.usda.gov/fnic/cgi-bin/nut_search.pl
14. X. Wu, G.R. Beecher, J.M. Holden, D.B. Haytowitz, S.E. Gebhardt, R.L. Prior (2004) "Lipophilic and Hydrophilic Antioxidant Capacities of Common Foods in the United States" J. Agric. Food Chem. 52:4026-4037.
X. Wu, R.L. Prior (2005) "Identification and Characterization of Anthocyanins by High-Performance Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry in Common Foods in the United States: Vegetables, Nuts and Grains"
J. Agric. Food Chem. 53:3101-3113.