Nuts are often maligned for their high fat content. However, they are a valuable part of a healthy diet, because they contain essential fats necessary for a healthy heart and brain. Fatty acids in almonds aren't abundant, but walnuts are a rich source.
Both almonds and walnuts are nutritious additions to your diet, but only walnuts contain omega-3 fatty acids.
What Are Omega-3s?
The body can make most of the different types of fats it needs. Not so with a type of fatty acid called omega-3. These are essential fats that must come from dietary sources.
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There are three main types of omega-3 fats: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). According to the Harvard T.H. Chan School of Public Health, ALA is the most common type of omega-3 fatty acid in the Western diet and is found in vegetable oils, nuts, flaxseeds and flaxseed oil, leafy vegetables and some animal fats, particularly those of grass-fed animals.
The other omega-3 fats, EPA and DHA, are found primarily in fish and seafood, especially fatty fish such as tuna, salmon and mackerel. Some foods are also fortified with these fats, which can be especially helpful for making omega-3 foods available to vegetarians.
Omega-3s are not only essential in your diet, but they're also essential for your health. Among their many functions is that they are part of the membranes surrounding all of your cells. They also provide many benefits for the health of your heart, lungs, immune system, eyes and endocrine system.
Omega-3s in Nuts
Figuring out the amounts of omega 3 in nuts can be confusing. Nuts provide several types of fats, including saturated, monounsaturated and polyunsaturated fats. In addition, there are further distinctions within each category.
Omega-3s are a type of polyunsaturated fat, but they are not the only type. There are also omega-6 and omega-9 polyunsaturated fats. Also referred to as n-3 fats, omega-3s comprise only a small part of the total polyunsaturated fats in nuts.
While both almonds and walnuts are good sources of polyunsaturated fats, only walnuts contain appreciable amounts of ALA omega-3. In fact, according to USDA data, one serving of almonds, or 1 ounce, provides only 0.001 grams of ALA. One 1-ounce serving of English walnuts, on the other hand, contains 2.542 grams.
But not all walnuts provide similar amounts. Black walnuts are considerably lower in ALA, providing 0.759 grams per 1-ounce serving, according to the USDA database.
Read more: The Benefits and Side Effects of Omega-3 -6 and -9
Conversion of ALA in Walnuts
English walnuts are high on the list of omega-3 nuts and plant foods, second only to chia seeds, which provide a little over 5 grams per ounce. However, none of that may matter, because the body can convert only small amounts of ALA to the forms of omega-3 it can actually use, EPA and DHA. According to the National Institutes of Health (NIH), the conversion rate may be less than 15 percent.
Therefore, you'd need to consume a lot of walnuts in order to meet your daily requirements for omega-3s. For that reason, the NIH reports that consuming EPA and DHA from fish or seafood or taking a supplement is the only reliable way to ensure you get enough of the nutrient.
Omega-3 Foods List
The Food and Nutrition Board of the National Academies of Medicine has set recommended daily intakes (RDIs) for omega-3 fatty acids, but not for each specific type. For women, the RDI is 1.1 grams, and for men the RDI is 1.6 grams. During pregnancy, people need 1.4 grams, and when breastfeeding, they need 1.3 grams.
In addition to the small amount of omega-3s in walnuts, you can get more abundant amounts in the following foods, according to the NIH:
- Salmon: 1.24 grams DHA and 0.59 grams EPA in 3 ounces
- Herring: 0.94 grams DHA and 0.77 grams EPA in 3 ounces
- Mackerel: 0.59 grams DHA and 0.43 grams EPA in 3 ounces
- Rainbow trout: 0.44 grams DHA and 0.40 grams per 3 ounces
- Cooked oysters: 0.14 grams DHA and 0.23 grams EPA per 3 ounces
Fatty fish are the most abundant source of DHA and EPA, and the American Heart Association recommends eating two 3.5-ounce servings each week to get adequate amounts. If you aren't able to reach this goal through your diet, your doctor may recommend that you take a supplement.
There are many different types of omega-3 supplements, from cod liver oil to krill oil, and they come in various dosages. There are also vegan omega-3 supplements derived from algae that provide EPA and DHA.
Only your doctor can tell you how much and which type of omega-3 supplement is right for you. It's important to speak with your doctor before taking an omega-3 supplement, as it may interact with certain medications you are taking or be contraindicated for some health conditions.
Read more: How Many Omega Fish Oil Pills Should You Take a Day?
Different Doses for Different Conditions
Aside from their basic physiological functions, omega-3 fatty acids have been studied for their potential effectiveness in the prevention and treatment of various medical conditions.
Cardiovascular disease (CVD): Results from research on the role of omega-3 fatty acids in the prevention and treatment of heart disease are mixed, but the Dietary Guidelines for Americans, 2015-2020, states that there is a strong connection between seafood consumption and reduced risk of CVD.
The guidelines report that the consumption of 8 ounces of seafood each week providing 250 grams of EPA and DHA per day may reduce cardiac deaths in healthy people and those with existing heart disease. Whether or not supplemental omega-3s are as effective is unclear.
Depression: Studies on the effects of omega-3 intake on depressive disorders yield conflicting results. Results of a meta-analysis published in March 2016 in the Journal of Epidemiology and Community Health revealed a strong association between high fish consumption and a lower risk of depression.
However, another research review published the previous year in the November 2015 issue of the Cochrane Database of Systematic Reviews failed to find any strong evidence that omega-3 fatty acid intakes of between 1 gram and 6.6 grams of EPA, DHA or a combination of the two had any beneficial effect on adults with major depressive disorder.
Cognitive function and dementia: Although widely promoted to improve cognitive function and prevent cognitive decline, it's unclear whether dietary and/or supplemental omega-3s are effective for these applications. A research review published in the American Journal of Clinical Nutrition in February 2016 showed evidence that a 100 milligram-increase in dietary fish was associated with a lower risk of dementia.
However, another meta-analysis published in the American Journal of Clinical Nutrition in December 2014 found that omega-3 supplements did not improve cognitive performance in adults or older folks.
- Harvard T.H. Chan School of Public Health: "Omega-3 Fatty Acids: An Essential Contribution"
- National Institutes of Health: "Omega-3 Fatty Acids"
- National Academies of Medicine: "Summary Tables, Dietary Reference Intakes"
- American Heart Association: "Eating Fish Twice a Week Reduces Heart Stroke Risk"
- Clinical Nutrition: "Blood Docosahexaenoic Acid and Eicosapentaenoic Acid in Vegans: Associations With Age and Gender and Effects of an Algal-Derived Omega-3 Fatty Acid Supplement"
- Health.gov: "Dietary Guidelines for Americans, 2015-2020: Chapter 1. A Closer Look Inside Healthy Eating Patterns"
- Journal of Epidemiology: "Fish Consumption and Risk of Depression: A Meta-Analysis."
- The Cochrane Database of Systematic Reviews: "Omega-3 Fatty Acids for Depression in Adults."
- American Journal of Clinical Nutrition: "Intakes of Fish and Polyunsaturated Fatty Acids and Mild-to-Severe Cognitive Impairment Risks: A Dose-Response Meta-Analysis of 21 Cohort Studies"
- American Journal of Clinical Nutrition: "Effect of N-3 Pufa Supplementation on Cognitive Function Throughout the Life Span From Infancy to Old Age: A Systematic Review and Meta-Analysis of Randomized Controlled Trials"