No aspect of walnuts has been better evaluated in the research than their benefits for the heart and circulatory system. Some review studies have emphasized the very favorable impact of walnuts on "vascular reactivity," namely, the ability of our blood vessels to respond to various stimuli in a healthy manner. In order to respond to different stimuli in a healthy way, many aspects of our cardiovascular system must be functioning optimally. These aspects include: ample presence of antioxidant and anti-inflammatory nutrients, proper blood composition, correct balance in inflammation-regulating molecules, and proper composition and flexibility in our blood vessel walls. Researchers have determined the ability of walnuts to have a favorable impact on all of these aspects.
What's New and Beneficial About Walnuts
- Recent evidence demonstrates that approximately 90% of the antioxidant phenols in walnuts are found in the skin, including key phenolic acids, tannins, and flavonoids. Some cookbooks will encourage you to remove the walnut skin - that whitish, sometimes waxy, sometimes flaky, outermost part of shelled walnuts. There can be slight bitterness to this skin, and that's often the reason that is given for removing it. However, we encourage you not to remove this phenol-rich portion.
- The form of vitamin E found in walnuts is somewhat unusual, and particularly beneficial. Instead of having most of its vitamin E present in the alpha-tocopherol form, walnuts provide an unusually high level of vitamin E in the form of gamma-tocopherol. Particularly in studies on the cardiovascular health of men, this gamma-tocopherol form of vitamin E has been found to provide significant protection from heart problems.
- Most U.S. adults have yet to discover the benefits of walnuts. A recent study has determined that only 5.5% of all adults (ages 19-50) consume tree nuts of any kind! This small percentage of people actually do a pretty good job of integrating tree nuts (including walnuts) into their diet, and average about 1.25 ounces of tree nuts per day. But the other 94.5% of us report no consumption of tree nuts whatsoever. In a recent look at the nutritional differences between tree nut eaters and non-eaters, researchers have reported some pretty notable findings: on a daily average, tree nut eaters take in 5 grams more fiber, 260 milligrams more potassium, 73 more milligrams of calcium, 95 more milligrams of magnesium, 3.7 milligrams more vitamin E, and 157 milligrams less sodium!
- Many of us can go local for our supply of walnuts. According to the latest trade statistics, 38% of all walnuts are grown in the U.S. Of that 38%, the vast majority (almost 90%) come from California, and particularly from the San Joaquin and Sacramento Valleys. Buying walnuts closer to home can provide great benefits from the standpoint of sustainability.
- In 2004, walnuts became one of the few individual foods for which a specific health benefit claim (heart disease prevention) was allowed on the product label by the U.S. Food and Drug Administration (FDA).
- Phytonutrient research on the antioxidant and anti-inflammatory benefits of walnuts has moved this food further and further up the ladder of foods that are protective against metabolic syndrome, cardiovascular problems, and type 2 diabetes. Some phytonutrients found in walnuts - for example, the quinone juglone - are found in virtually no other commonly-eaten foods. Other phytonutrients - like the tannin tellimagrandin or the flavonol morin - are also rare and valuable as antioxidants and anti-inflammatory nutrients. These anti-inflammatory and antioxidant phytonutrients also help explain the decreased risk of certain cancers - including prostate cancer and breast cancer - in relationship to walnut consumption.
Walnuts are part of the tree nut family, a food family that has a wealth of potential health benefits. In the majority of dietary studies, approximately one ounce of tree nuts per day is the minimal amount needed to provide statistically significant benefits, and that's the amount we recommend that you incorporate into your daily diet. In the case of walnuts, one ounce means about 7 shelled walnuts, or 14 walnut halves. Of course, since tree nuts (including walnuts) are a high-calorie food, it's important to incorporate tree nuts into an overall healthy diet that remains on target in terms of calories. Luckily, research has shown that many people are able to take this step with good success in terms of overall caloric intake.
Walnuts provide numerous health benefits including:
- Cardiovascular health
- Metabolic syndrome protection
- Anti-cancer benefits
- Bone health support
- Anti-inflammatory benefits
- Potential weight loss support
For more details on walnuts' health benefits, see this section of our walnuts write-up.
Walnuts are an excellent source of anti-inflammatory omega-3 essential fatty acids, in the form of alpha-linolenic acid (ALA). Walnuts are also rich in antioxidants, including being a very good source of manganese and copper. They are also a good source of molybdenum and the B vitamin biotin. Many other minerals are provided by walnuts in valuable amounts. These minerals include calcium, chromium, iron, magnesium, phosphorus, potassium, selenium, vanadium, and zinc. Vitamin B6, while not especially concentrated in walnuts, may be more bioavailable in this food. In terms of phytonutrients, walnuts contain antioxidant and anti-inflammatory compounds, including more than a dozen phenolic acids, numerous tannins (especially ellagitannins, including tellimagrandins), and a wide variety of flavonoids. The vitamin E composition of walnuts is also of special mention, since there is an unusual concentration of the gamma-tocopherol form of vitamin E in this tree nut.
For more on this nutrient-rich nut, including references related to this Latest News, see our write-up on walnuts.