Nuts; Types, Nutritional Value, Uses, Health Benefits of Nuts

Nuts is a fruit composed of an inedible hard shell and a seed, which is generally edible. In general usage, a wide variety of dried seeds are called nuts, but in a botanical context “nut” implies that the shell does not open to release the seed (indehiscent). The translation of “nut” in certain languages frequently requires paraphrases, as the word is ambiguous.[1]

Most seeds come from fruits that naturally free themselves from the shell, unlike nuts such as hazelnuts, chestnuts, and acorns, which have hard shell walls and originate from a compound ovary. The general and original usage of the term is less restrictive, and many nuts (in the culinary sense), such as almonds, pecans, pistachios, walnuts, and Brazil nuts,^[2] are not nuts in a botanical sense. Common usage of the term often refers to any hard-walled, edible kernel as a nuts

Types of Nuts

Some fruits and seeds that do not meet the botanical definition but are nuts in the culinary sense are

• Almonds are the edible seeds of drupe fruits — the leathery “flesh” is removed at harvest.
• Brazil nut is the seed from a capsule.
• Candlenut (used for oil) is a seed.
• Cashew is the seed^[4] of a drupe fruit with an accessory fruit.
• Chilean hazelnut or Gevuina
• Macadamia is a creamy white kernel of a follicle type fruit.
• Malabar chestnut
• Pecan is the seed of a drupe fruit
• Mongongo
• Peanut is a seed and from a legume type fruit (of the family Fabaceae).
• Pili nut is the seed of the tropical tree Canarium ovatum which grows in the Philippines, Indonesia, and Papua New Guinea.
• Pine nut is the seed of several species of pine (coniferous trees).
• Pistachio is the partly dehiscent seed of a thin-shelled drupe.
• Walnut (Juglans) is the seed of a drupe fruit
• Yeheb nut is the seed of a desert bush, Cordeauxia edulis [4]

What are the best low carb nuts? And which nuts have the most nutrients?

This article provides the answers to all these questions and more.

Nutrition Summary (per ounce / 28g) of Nuts

First, here are the main macronutrient details for every nut at a glance.

Different Types of Nuts

For each nut, you can see a data table with the macronutrient details and the amounts of omega 3 and 6.

You will also find a list of the six most significant vitamins and minerals each nut contains and a breakdown of the benefits and drawbacks.

1. Almonds (per ounce / 28g) (1)

Almonds originated in the Middle East and only recently spread around the world. They are one of the healthiest kinds of nuts and absolutely packed with beneficial nutrients.

Almonds also contain the following major nutrients;

• Vitamin E: 37% RDA
• Manganese: 32% RDA
• Magnesium: 19% RDA
• Vitamin B2: 17% RDA
• Copper: 14% RDA
• Phosphorus: 14% RDA

Benefits

• Almonds contain large amounts of fat and moderate amounts of both protein and carbs.

• On the positive side, almonds have some very beneficial impacts on blood sugar. Research shows that they reduce blood sugar and insulin levels in diabetics as well as non-diabetics (2, 3, 4).

• As high blood sugar and insulin levels are associated with every major chronic disease in the book, this is a great benefit.

• Further to this, people consuming almonds show lower levels of oxidative damage, a healthier lipid profile, and higher satiety levels (5, 6, 7).

Drawbacks

• Almonds contain a large amount of phytic acid, a known antinutrient which may block absorption of minerals. However, phytate has both positive and negative effects on health and is likely beneficial in small amounts. The key: stick to a sensible amount (8, 9).

• Compared to other kinds of nuts, the omega 6 to 3 ratio in almonds is the highest. However, providing you’re getting enough omega 3 from oily fish and pastured animal foods, a few servings a week should be fine.

2. Brazil Nuts (per ounce / 28g) (10)

As you can probably guess, Brazil nuts originate—and still mainly grow—in the Brazilian forests.

Brazil nuts are the biggest out of all types of nuts and they are the world’s biggest source of dietary selenium.

The most significant vitamins and minerals in Brazil nuts are;

• Selenium: 767% RDA
• Magnesium: 26% RDA
• Copper: 24% RDA
• Phosphorus: 20% RDA
• Manganese: 17% RDA
• Vitamin B1: 12% RDA

Benefits

• Brazil nuts are the single best source of selenium in the world, an important mineral for health. However, some people are becoming deficient in it due to selenium soil depletion; just 2 or 3 brazil nuts provide a huge amount of the mineral (11).

• Studies show that Brazil nuts improve lipid profiles. For example, just several hours after a 20-gram dose LDL and triglyceride levels significantly drop and HDL increases (12).

• Brazil nut consumption improves the body’s antioxidant status. A randomized controlled trial also shows that Brazil nuts decrease oxidative stress and improve the lipid profile (13, 14).

Drawbacks

• Similar to almonds, Brazil nuts also contain a large amount of phytic acid.

• Brazil nuts contain such a high amount of selenium that there are concerns over potential overdose and toxicity issues. In a trial, school children eating 15-30g per day all had excessive selenium levels associated with toxicity risk (selenosis). With Brazil nuts, less is definitely more; a handful per week is more than enough (15).

3. Cashew Nuts (per ounce / 28g) (16)

Cashews predominantly come from Asia and Africa, with most commercial nuts coming from Vietnam and Nigeria.

They are one of the most popular varieties of nut and contain a nice mix of nutrients.

Cashew provides a significant amount of the following nutrients;

• Copper: 31% RDA
• Manganese: 23% RDA
• Magnesium: 20% RDA
• Phosphorus: 17% RDA
• Vitamin K: 12% RDA
• Iron: 10% RDA

Benefits

• Raw cashew nuts contain a significant level of some health-protective compounds, such as beta-carotene, the antioxidants lutein and zeaxanthin, vitamin E, and oleic acid. Also found in eggs, lutein and zeaxanthin are very beneficial for our eyesight and help protect against macular degeneration (17).

• Cashew nuts provide a decent source of copper, manganese, and magnesium.

Drawbacks

• A randomized, controlled trial investigating the effects of cashew nuts on the metabolic syndrome found that cashew nut intervention diets had no effect. Compared to the control group, the cashew nut group failed to show any improvements in cholesterol, blood pressure, or blood glucose readings (18).

• Cashew nut allergies are common, and they can be even more serious than peanut allergies. For example, studies show that the risk of severe reactions, including anaphylaxis, are more common than in allergic reactions to peanuts (19, 20).

• Cashew nuts are much higher in carbohydrate than other nuts, making them a poor choice for those who are focusing on low carb foods.

4. Chestnuts (per ounce / 28g) (21)

Chestnuts are different from other kinds of nuts in that they are predominantly starchy carbohydrate.

As a result, if you’re looking for healthy fats then it’s better to look elsewhere.

The highest occurring nutrients in chestnuts are;

• Manganese: 17% RDA
• Vitamin C: 12% RDA
• Copper: 7% RDA
• Vitamin B6: 7% RDA
• Potassium: 5% RDA
• Vitamin B1: 5% RDA

Benefits

• They taste great, particularly on a cold winter’s day.

• Chestnuts provide a decent amount of manganese, but there aren’t any other standout nutrients. Also, the positive health impacts are small in comparison to other nuts — very few studies show any significant benefits.

Drawbacks

• Chestnuts are very high in carbs and low in fat; the very opposite of most nuts! In other words, don’t think of them as a source of healthy fats — they are not.

5. Hazelnuts (per ounce / 28g) (22)

As one of the most popular types of nuts, hazelnuts are delicious and used in all sorts of food products.

In short, they are one of the most nutritious nuts around and have numerous research-backed benefits.

The standout nutrients in hazelnuts are;

• Manganese: 86% RDA
• Copper: 24% RDA
• Vitamin E: 21% RDA
• Vitamin B1: 12% RDA
• Magnesium: 11% RDA
• Vitamin B6: 8% RDA

Benefits.

• Hazelnuts have protective effects against cardiovascular disease. In fact, participants consuming a hazelnut-enriched diet have improved arterial dilation, reductions in LDL and triglycerides, and increases in HDL. Furthermore, oxidized-LDL levels and inflammatory markers are “significantly reduced” (23).

• A randomized study involving type 2 diabetes patients showed that a hazelnut-enriched diet helps prevent a reduction in HDL levels. This symptom commonly occurs in diabetics and it is a significant cardiovascular risk factor. Also, compared to patients on a control diet, the hazelnut group had significant reductions in triglycerides (24).

• A systematic review and meta-analysis of nine clinical trials showed that hazelnuts reliably and consistently lower cardiovascular risk factors (25).

• Hazelnuts are a significant source of polyphenols and exert powerful antioxidant effects on the body (26, 27).

Drawbacks

• There aren’t many drawbacks with hazelnuts, but similar to all nuts they can cause allergic reactions. And sometimes these effects can be severe (28).

6. Macadamia (per ounce / 28g) (29)

Macadamias are fairly expensive, and they are one of the least nutrient-dense types of nuts.

However, they are the most delicious. With a yummy, buttery taste, no other nuts come close.

The major nutrients present in macadamia nuts are;

• Manganese: 58% RDA
• Vitamin B1: 22% RDA
• Copper: 11% RDA
• Magnesium: 9% RDA
• Iron: 6% RDA
• Phosphorus: 5% RDA

Benefits

• The taste. Is there a tastier nut? Not many foods top macadamias!

• Macadamias are very low in carbohydrate and high in fat, with an insignificant amount of omega-6. As most nuts contain a large source of omega-6, this can be helpful for those trying to watch their omega 6 to 3 ratio.

• Macadamia nuts contain virtually no phytic acid.

• Consumption of macadamias decreases the risk of cardiovascular disease by reducing triglycerides and increasing HDL levels (30).

• Animal studies show that macadamia nuts reduce inflammation and aid in muscle repair following strenuous exercise (31, 32).

Drawbacks

• The price; macadamias are typically the most expensive nut. However, you can get them for a reasonable price if you’re willing to buy online in bulk.

7. Peanuts (per ounce / 28g) (33)

Although they are technically a legume, peanuts are one of the most popular sorts of ‘nuts’.

They are usually available either salted, dry-roasted or as a nut butter,

Peanuts are not technically a nut; they are a legume. However, as they are known as a nut in popular culture, they make the list.

Per ounce, the most significant nutrients in peanuts are;

• Manganese: 24% RDA
• Vitamin B3: 17% RDA
• Vitamin B9: 17% RDA
• Copper: 16% RDA
• Magnesium: 12% RDA
• Vitamin B1: 12% RDA

Benefits

• A cardiovascular risk intervention group were provided with peanuts for a 3 or 8-week study. Participants all experienced lower triglyceride levels and increased serum levels of minerals, particularly magnesium (34).

• Peanut butter is tasty and (depending on the product) healthy way to get more nuts into the diet.

Drawbacks

• Peanut allergy is a very real, prevalent, and serious condition. This allergy affects approximately 1% of infants and 0.6% of children, and it can be fatal (35).

8. Pecan (per ounce / 28g) (36)

Pecans are one of the most popular types of nuts in baking and for desserts. However, they taste just great on their own.

Pecans offer a range of vitamins and minerals and provide large amounts of;

• Manganese: 63% RDA
• Copper: 17% RDA
• Vitamin B1: 12% RDA
• Zinc: 8% RDA
• Magnesium: 8% RDA
• Phosphorus: 8% RDA

Benefits

• Pecans are one of the most polyphenol-rich nuts in existence. Studies show that these compounds are absorbable and contribute to our body’s defense systems (37, 38).

• Research shows that daily consumption of pecans reduces triglyceride levels (-11%) and increases high-density lipoprotein (+6%) (39).

Drawbacks

• The risk of allergy.

• Pecans contain a significant amount of omega-6, and the omega 6 to 3 ratio is very high.

9. Pine Nuts (per ounce / 28g) (40)

Pine nuts are one of the least common varieties of nut.

Despite this, they are increasing in popularity over recent years and have several health benefits.

Pine nuts provide a great source of the following vitamins and minerals;

• Manganese: 123% RDA
• Vitamin K: 19% RDA
• Copper: 19% RDA
• Magnesium: 18% RDA
• Phosphorus: 16% RDA
• Vitamin E: 13% RDA

Benefits

• Pine nuts provide an excellent source of manganese.

• Similar to other tree nuts, pine nuts contain a range of health-protective polyphenolic compounds (41).

• Animal studies suggest that pine nuts may help improve mitochondrial oxidative metabolism, showing promise for use as a tool to fight obesity (42).

Drawbacks

• Together with several other nuts, pine nuts also contain a significant amount of omega-6 and they have minimal omega-3 content.

• Pine nut allergies are prevalent and often result in anaphylactic shock (43).

• Cacogeusia, otherwise known as “pine mouth,” is occasionally a problem with pine nuts. Following ingestion of pine nuts, some people experience a metallic or bitter taste in their mouth. Surprisingly, this phenomenon can last for up to two weeks, and other symptoms include abdominal cramping and nausea (44).

10. Pistachio (per ounce / 28g) (45)

Different from other types of nuts, pistachios usually come in their shell. They originate from the Middle East.

Pistachios provide the following nutrients per ounce;

• Vitamin B6: 24% RDA
• Copper: 18% RDA
• Manganese: 17% RDA
• Vitamin B1: 16% RDA
• Phosphorus: 14% RDA
• Magnesium: 8% RDA

Benefits

• Salted pistachios are delicious!

• Replacing carbohydrate-based snacks with pistachios significantly reduces circulating triglyceride levels (46).

• A randomized trial suggests that pistachios may have a positive impact on exercise performance, and on oxidative stress levels following exercise (47).

• A further randomized trial found that pistachios “beneficially affect CVD risk factors in a dose-dependent manner” (48).

• Randomized controlled trials show that a daily serving of pistachios significantly reduces LDL-oxidation in patients with hypercholesterolemia (49).

Drawbacks

• Eating pistachios often involves a fair bit of work — and sore thumbs from opening those shells!

• Allergies.

• The source is important – it isn’t unusual for pistachios to contain aflatoxins (mold) over the legal “safe” limit (50, 51).

11. Walnut (per ounce / 28g) (52) 

Walnuts predominantly come from China, and they are one of the most popular types of nuts.

Not only are they used as a snack but they are also a major ingredient in a wide range of recipes.

The major micronutrients in walnuts are;

• Manganese: 48% RDA
• Copper: 22% RDA
• Magnesium: 11% RDA
• Phosphorus: 10% RDA
• Vitamin B6: 8% RDA
• Vitamin B9: 7% RDA

Benefits

• Walnut consumption improves endothelial function, decreases blood pressure, lowers blood glucose, and reduces diabetes risk (53, 54).

• The study of 7447 elderly participants found that walnut consumption decreased cardiovascular risk and extended lifespan (55).

• Walnuts contain significant amounts of phytochemicals and healthy fats. Notably, they seem to have positive effects on brain health and help maintain healthy cognitive function (56, 57).

• The omega 6 to 3 ratio is the smallest out of all nuts. However, there is a large amount of omega-6; 10 grams per ounce.

Drawbacks

• Similar to most nuts, serious allergies are possible.

References

1. https://en.wikipedia.org/wiki/Nut_(fruit)
2. https://www.ncbi.nlm.nih.gov/pubmed/24500935
3. http://drc.bmj.com/content/3/1/e000115
4. http://www.naturalmedicinejournal.com/journal/2013-09/eating-walnuts-extends-longevity
5. http://ajcn.nutrition.org/content/88/3/651.full
6. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0113725