Understanding Nuts and Seeds

In light of the recently published STALL (Statins and Almonds to Lower Lipoproteins) trial, I would like to use this forum to discuss some of the health benefits of nuts and seeds. The results of this study are important as they suggested that regularly consuming almonds help reduce the amount of and particle size of LDLs (bad cholesterol).

Before getting into a discussion about individual nuts and seeds, let’s immediately address the fact that peanuts are not nuts at all. Peanuts are legumes. Examples of other legumes include chickpeas, beans and lentils.

Differences between Peanuts and Nuts

• Peanuts have a high ratio of omega-6 polyunsaturated fatty acids, which can cause inflammation.
• Peanuts often contain Aflatoxin, a cancer-causing mold.
• Peanuts also contain peanut oil lectin, a protein that has been shown to induce atherosclerosis in primates. In humans, there are a few studies revealing improvement in lipid markers such as triglycerides and LDL. 

Although I generally advise my patients to choose nuts, over peanuts because of the nutritional superiority of nuts, if you really want include some peanut butter as a part of your regular diet, choose a brand without hydrogenated oils and sugar.

General Facts on Nuts and Seeds

Nuts are small packages of fat with some protein and carbohydrate. The ratios of fats in each nut determine its health properties and ability to resist oxidation, a process in which oxygen is metabolized, damaging cells and raising the risk of disease.

Nuts higher in polyunsaturated fat tend to be more susceptible to oxidation; whereas, nuts with less polyunsaturated fat and more monounsaturated fat are usually more resistant to oxidation. It’s important to understand the fatty acid composition of nuts, especially if you prefer eating roasted nuts, as heat causes fats to oxidize.

Interestingly, the fat in nuts is contained in individual cells protected by thick cell walls complete with high amounts of plant-based chemicals and vitamin E, both known to prevent oxidation of fat. As a result, eating nuts has been shown to improve the levels of oxidized bad cholesterol (LDLs) and to reduce the risk of fat oxidizing. Once fats oxidize, they are much more likely to contribute to plaque formation.

In the following examples, look at the ratios of monounsaturated fatty acids (MUFA) to polyunsaturated fatty acids (PUFA) and you’ll see that macadamia nuts and hazelnuts have the highest ratios, suggesting that they are more resistant to oxidation.

Health benefits of nuts

Almonds

• Reduce 24 hour insulin secretion
• Reduce blood sugar in diabetic patients
• Improve satiety and post-prandial glucose when consumed as snacks
• Supply potent prebiotic fibers (a prebiotic is something that is a food source for gut bacteria)
• Reduce lipid oxidation and improve the fatty acid profile
• 105 calories/ounce (24 nuts)
• 8.8 grams MUFA vs 3.4 grams PUFA vs. 1 gram saturated fat

Pistachios

• Improve markers of metabolic syndrome
• Reduce postprandial blood sugar particularly after a high carb meal
• Possess potent prebiotic fiber shown to induce healthier gut bacteria (remember a healthy gut biome makes us healthier)
• 159 calories/ounce
• 5.8 grams MUFA vs 3.8 grams PUFA vs 1.6 grams SFA

Macadamias

• Have very little vitamin E because they have very little fragile PUFA requiring protection (see the impressive MUFA to PUFA ratio below)
• Lower biomarkers of oxidative stress
• Improve the lipid profiles of hyperlipidemic men and women
• Are low in omega 6 PUFA’s (linoleic acid)
• Are very calorie dense
• 203 calories/ounce (12 nuts)
• 16.7 grams of MUFA with only 0.4 grams PUFA and 3.4 grams SFA

Brazil nuts

• Are higher in selenium than any other nut. Selenium is an important antioxidant and helps maintain a healthy immune system, fight cancer, and even cardiovascular disease. Just two nuts a day have all the selenium you’ll need.
• Improve lipid profiles
• Lower inflammatory markers
• Improve glutathione activity
• 186 calories/ounce (8 nuts)
• 7 grams MUFA vs. 5.8 grams PUFA vs. 4.3 grams SFA

Walnuts

• Lower apoB and non-HDL cholesterol
• Improve endothelial function
• Lower markers of oxidative stress
• Increase cholesterol efflux (reverse cholesterol transport)
• Higher in PUFA than most other nuts (which make them a good source of plant based Omega 3’s but also makes them quick to oxidize)
• Paleo friendly because best omega 6:omega 3 ratio of any nut. Our pre-agricultural ancestors consumed a diet very high in omega 3’s and low in omega 6’s
• 185 calories/ounce (14 halves)
• 2.5 grams MUFA vs. 11 grams PUFA vs. 1.7 grams SFA

Hazelnuts

• The skin is actually one of the richest sources of polyphenolic compounds with 25 times the antioxidant capacity of blackberries, 10 times that of espresso, and 8 times that of dark chocolate
• Reduce apoB values
• Reduce LDL oxidation
• Boost vitamin E levels
• Nutella (sweetened hazelnut butter) doesn’t count.
• 178 calories/ounce (12 nuts)
• 12.9 grams MUFA vs. 2.2 grams PUFA vs. 1.3 grams SFA

Cashews

• Are not as good at positively impacting blood glucose or markers of oxidation
• Did improve baroreflex sensitivity in one study
• Higher in carbs than any of the other nuts
• Are my favorite nut
• 157 calories/ounce (18 nuts)
• 6.7 grams MUFA vs. 2.2 grams PUFA vs. 2.2 grams SFA

Pecans

• Also lower LDL oxidation
• Improve the lipid profiles of men and women
• Reduce inflammatory markers
• 196 calories/ounce (15 halves)
• 11.6 grams MUFA vs. 5.8 grams PUFA vs. 1.8 grams SFA

Health benefits of seeds

Flaxseeds

• Consumed daily are one of the most potent dietary intervention with respect to anti-hypertensive effect
• Reduce oxidized LDL
• Should be milled or ground for best effect
• May help reduce menopausal symptoms
• Are very high in magnesium which is the likely mechanism whereby they reduce blood pressure.

Chia seeds

• Reduced CRP modestly
• Like flaxseeds, Chia seeds are a source of short chain omega 3 fatty acids. The truly beneficial omega 3’s are long chain omega 3’s. Our bodies are very inefficient at converting plant based omega 3’s into long chain beneficial omega 3’s.
• Had no effect on bodyweight or disease risk factors in overweight adults

Sunflower seeds

• Have considerable levels of antioxidant compounds
• Are rich in phytosterols which may lower cholesterol (but remember that certain patients are capable of hyper-absorbing phytosterols which can lead to atherosclerotic effects…unless of course you’re using Zetia)

Sesame seeds

• Improved signs and symptoms of osteoarthritis in a group of patients
• Reduced triglycerides
• Reduced LDL oxidation
• Improved antioxidant capacity and lowered blood pressure in pre-hypertensives

Pumpkin seeds

• Reduced nocturnal urination in patients with overactive bladders
• Have antihypertensive effects
• One year of supplementation in men with BPH reduced their International Prostate Symptom Score

Please keep in mind that while seeds are nutritious, they are also high in inflammatory polyunsaturated fats and should be consumed in limited quantities, despite the health benefits.