Elevated levels of serum cholesterol represent a major risk factor for coronary heart disease. In fact, there’s actually a direct relationship between not only plasma levels of total and low-density lipoprotein (LDL) cholesterol and coronary heart disease, but also coronary mortality.
In Canada, the current guidelines recommend screening of men over 40 and women over 50 (or postmenopausal) which consists of a fasting lipid profile (total cholesterol, HDL, LDL, and triglycerides). Additionally, adults who have other risk factors such as diabetes, hypertension, obesity, smokers, erectile dysfunction, among others, or who have a family history of hypercholesterolemia should be screened at any age.
Target cholesterol levels are often determined clinically using a Framingham risk score. For those who have elevated cholesterol levels, there are a number of lifestyle changes which are also often recommended including smoking cessation, weight loss, daily exercise, stress management and dietary modifications.
Some dietary approaches or specific dietary supplements have been beneficial at lowering cholesterol levels. This list includes fish oil (omega 3 fatty acids), soy, red yeast rice, plant sterols, dietary fiber, green tea, as well as diets such as the DASH diet and Mediterranean diet.
On that note, the question remains as to what effect consuming pistachio nuts have on lowering serum cholesterol…
Study 1: Pistachio diet improves serum lipid profiles in patients with erectile dysfunction
Though many of us are aware of common cardiovascular risk factors such as hypertension, high cholesterol levels, diabetes, cigarette smoking, and>obesity, it’s important to keep in mind that the same process (atherosclerosis) and consequently risk factors that affects the health of your coronary arteries can also predispose you to erectile dysfunction.
The obvious reason for promulgating this information is the likelihood that the same men who’re reluctant to manage these health conditions (until later on in the course of these disease processes) are probably the same ones who happily shell out billions of dollars annually for drugs like Vigra® or Cialis®.
One recent study published in the International Journal of Impotence research , found that men with erectile dysfunction who consumed 100 grams of pistachios per day resulted in statistically significant reductions in cholesterol levels.
Total cholesterol was reduced by 17% while LDL cholesterol was specifically reduced by 20%. In contrast, HDL (or good cholesterol) was increased by 24%. As an aside, the researchers also found that this diet resulted in statistically significant improvements in erectile function parameters. :p
To put these numbers in perspective, statin medications such as simvastatin or lovastatin typically lower LDL cholesterol levels in the range of 26-54%.
Study 2: Effect of pistachio diet on cholesterol levels, inflammation, and oxidative stress
Participants in a study published in the journal, Nutrition , were switched to a Mediterranean diet for 4 weeks followed by another 4 weeks in which they replaced 20% of their monounsaturated fat intake with pistachios. Of note, the participants were healthy males with normal levels of cholesterol
The researchers found:
Compared with the Mediterranean diet, the pistachio diet decreased glucose (P<0.001, -8.8+/-8.5%), low-density lipoprotein (P<0.001, -23.2+/-11.9%), total cholesterol (P<0.001, -21.2+/-9.9%), and triacylglycerol (P=0.008, -13.8+/-33.8%) significantly and high-density lipoprotein (P=0.069, -3.1+/-11.7%) non-significantly.
In fact, they concluded:
In this trial, we demonstrated that a pistachio diet improved blood glucose level, endothelial function, and some indices of inflammation and oxidative status in healthy young men. These findings are in accordance with the idea that nuts, in particular pistachio nuts, have favorable effects beyond lipid lowering that deserve to be evaluated with prospective follow-up studies.
[box type=”note”]Again, this study shows a surprising reduction in LDL cholesterol levels of 23%.[/box]
Study 3: Pistachio diet in those with moderately elevated cholesterol levels
Researchers from Iowa previously published the results of a study on the pistachio diet in those with moderate cholesterolemia (serum cholesterol levels greater than 210 mg/d or 5.4 mmol/L) .
For this study, participants were randomized to a diet consisting of a whopping 15% of their total caloric intake from pistachios. Unfortunately, it did not find that the diet resulted in statistically significant reductions in LDL or total cholesterol nor increases in HDL.
However, they did conclude:
“A diet consisting of 15% of calories as pistachio nuts (about 2-3 ounces per day) over a four-week period can favorably improve some lipid profiles in subjects with moderate hypercholesterolemia and may reduce risk of coronary disease.”
Study 4: Pooled analysis for nut consumption and serum cholesterol levels
Okay, you didn’t think I would keep going summarizing every study on pistachio nuts did you? 🙂 That’s just nuts! Instead, let’s take a look at some pooled or summarized data.
Researchers from Loma Linda University published a pooled analysis of 25 intervention trials on nut consumption and cholesterol levels (not limited to pistachio nuts).
Here were their results:
“With a mean daily consumption of 67 g of nuts, the following estimated mean reductions were achieved: total cholesterol concentration (10.9 mg/dL [5.1% change]), low-density lipoprotein cholesterol concentration (LDL-C) (10.2 mg/dL [7.4% change]), ratio of LDL-C to high-density lipoprotein cholesterol concentration (HDL-C) (0.22 [8.3% change]), and ratio of total cholesterol concentration to HDL-C (0.24 [5.6% change]) (P < .001 for all).”
Interestingly, the authors of this study noted a dose-response effect. In other words, the more nuts participants in these studies consumed,
the nuttier they were the greater the impact was on improving their cholesterol levels.
Why are pistachios so healthy to eat?
In comparison to other nuts, they are high in lutein, vitamin e, and beta carotene. In addition, pistachios predominantly monounsaturated fats with a very low content of saturated fats. They contain the highest levels of phytosterols among tree nuts and significant levels of magnesium, potassium, and the amino acid, arginine.
- Aldemir M, Okulu E, Neşelioğlu S, Erel O, Kayıgil O. Pistachio diet improves erectile function parameters and serum lipid profiles in patients with erectile dysfunction. Int J Impot Res. 2011 Jan-Feb;23(1):32-8. Epub 2011 Jan 13.
- Sari I, Baltaci Y, Bagci C, Davutoglu V, Erel O, Celik H, Ozer O, Aksoy N, Aksoy M. Effect of pistachio diet on lipid parameters, endothelial function, inflammation, and oxidative status: a prospective study. Nutrition. 2010 Apr;26(4):399-404. Epub 2009 Jul 31.
- Sheridan MJ, Cooper JN, Erario M, Cheifetz CE. Pistachio nut consumption and serum lipid levels. J Am Coll Nutr. 2007 Apr;26(2):141-8.
- Sabaté J, Oda K, Ros E. Nut consumption and blood lipid levels: a pooled analysis of 25 intervention trials. Arch Intern Med. 2010 May 10;170(9):821-7.