California Walnuts | Essential Food for Health

Questions & Answers

Below you will find answers to the questions about walnuts, nutrition and health people ask most frequently. If you don't find the answer you're looking for here, please send us a message.

Q. I have heard walnuts are good for my health. Aren’t all nuts the same?

A. Walnuts are unique compared to other nuts because they are predominantly composed of polyunsaturated fatty acids (PUFA, both omega-3 and omega-6) rather than monounsaturated fatty acids (MUFA), which are present in most other nuts. Walnuts are the only nut that contain a significant amount of omega 3 fatty acids. A one-ounce serving of walnuts provides 2.6 grams of omega-3 fatty acid, or 200% of the Daily Value, as well as other health-promoting nutrients and bioactive components. Numerous studies have shown that adding walnuts to the diet produces favorable health outcomes, including lowering total and LDL cholesterol, improving LDL:HDL ratios and reducing inflammation associated with increased heart disease risk.

Q. I use the 2005 MyPyramid to help me make the right food choices for a healthy diet. Where do walnuts fit in?

A. Including healthy fats in the diet is one of the key messages of the individualized MyPyramid food guidance system. The new MyPyramid symbol illustrates recommendations from the 2005 Dietary Guidelines for Americans where an emphasis to consume more polyunsaturated fat (and less saturated and trans fat) in order to achieve a healthy diet is made. Specific guidelines were given to increasing intake of essential fatty acids, including omega-3 fatty acids. Plant sources of polyunsaturated omega-3 fatty acids such as walnuts are specifically noted.

Q. Are the omega 3 fatty acids in fish the same as the ones in walnuts?

A. The omega-3 fatty acid alpha linolenic acid (ALA) is the precursor or “parent” to the two long-chain omega 3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Walnuts contain ALA and fatty fish contain EPA and DHA. Metabolic reactions enable ALA to be converted into EPA and DHA.
While some studies have suggested that the conversion of the omega-3 fatty acid ALA to the longer-chain fatty acids, EPA and DHA, could be below 10 percent in humans, there is a potentially wide variation in the rate of conversion. Research also indicates that ALA provides health benefits independent of conversion to longer chain fatty acids.

Q. Is there a dietary reference intake (DRI) for all omega-3 fatty acids or only for alpha-linolenic acid?

A. In September 2002, the National Academies' Institute of Medicine (IOM) released the “Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Protein and Amino Acids (A Report of the Panel on Macronutrients, Subcommittees on Upper Reference Levels of Nutrients and Interpretation and Uses of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes) This report addresses the new Dietary Reference Intakes (DRIs), which include three reference intakes: Estimated Average Intake (EAR), Adequate Intake (AI) and Upper Intake Level (UL). The AI for alpha linolenic acid (ALA) is 1.6 and 1.1 grams per day for men and women, respectively. The DRI is for ALA only.

Q. How does heating (such as toasting, boiling or frying) effects the omega-3 content of the walnut?

A. Omega-3 fatty acid loss is insignificant (<5%) when walnuts are roasted, toasted or baked for short periods of time.

Q. I am counting carbs. Where do walnuts fall in the land of Atkins?

A. Walnuts contain very little carbohydrate. One ounce of walnuts contains 4 grams carbohydrates and 2 grams fiber

Q. What are the major differences between black and English walnuts?

A. California Walnuts are English walnuts. Their scientific name is Juglans Regia. English walnuts are native to the Middle East. The black walnut is a native American species. Currently the black walnut is used mainly as a rootstock for English walnuts. The meats are tasty but thanks to a very thick shell, they are a lot of work to crack and remove from the shell. Nutritionally speaking black walnuts contain approximately 10% less total fat and approximately 80% less omega 3 fatty acids than English walnuts. According to the USDA Nutrient Database, SR 19, one ounce of black walnuts contains 16.7 grams of total fat and .57 grams of omega 3’s. One ounce of English walnuts contains 18.5 grams of total fat and 2.6 grams of omega 3’s.

Q. I am looking for weight equivalents for walnut pieces and halves.

A. According the USDA Database Standard Reference 19:

1 walnut half = 2 grams
1 ounce of walnuts = 14 halves
1 cup walnut pieces = 120 grams
1 cup walnuts, chopped = 120 grams
1 cup shelled walnuts = 50 halves = 100 grams

Q. We finely chop walnuts and put them on our breakfast cereal. Is it okay to keep them in a container and use as needed? Will they spoil if not refrigerated? Do we loose any of the nutrition by chopping them up?

A. Walnuts are rich in polyunsaturated fat, which, when exposed to heat, does oxidized quickly, so if you chop them up it is best to store in an airtight container in the refrigerator or freezer to ensure freshness. Chopping does not affect the nutritional value as long as they are stored properly

Q. I have angina and I am interested in any positive recommendations to keep my heart healthy, thus my interest in walnuts. I asked my cardiologist and his response was "Walnuts are good for your heart, but you will gain lots of weight". Are they THAT fattening?

A. The latest research affirms that the health benefits from eating walnuts do not come at the expense of weight gain. Researchers have noted in many walnuts studies that subjects did not gain weight when walnuts were substituted for other fat in reduced-calorie diets. People reported feeling more satisfied; many said walnuts made it easier to stick to a diet. A recommended portion of walnuts is one ounce.