WH FOOD WALNUT

Walnuts
What's New and Beneficial about Walnuts
Researchers are convinced - more than ever before - about the nutritional
benefits of walnuts when consumed in whole form, including the skin. We now
know that approximately 90% of the phenols in walnuts are found in the skin,
including key phenolic acids, tannins, and flavonoids. Some websites 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 websites give 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.
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.
WHFoods Recommendations
Walnuts are part of the tree nut family. This food family includes Brazil nuts,
cashews, hazelnuts (filberts), macadamia nuts, pecans, pine nuts, pistachios and
walnuts. It would be difficult to overestimate the potential health benefits
associated with this food family! 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 not only taste great but are a rich source of heart-healthy
monounsaturated fats and an excellent source of those hard to find omega-3 fatty
acids. Like most nuts, they can easily be added to your Healthiest Way of
Eating. Just chop and add to your favorite salad, vegetable dish, fruit, or
dessert.


This chart graphically details the %DV that a serving of Walnuts provides for
each of the nutrients of which it is a good, very good, or excellent source
according to our Food Rating System. Additional information about the amount of
these nutrients provided by Walnuts can be found in the Food Rating System
Chart. A link that takes you to the In-Depth Nutritional Profile for Walnuts,
featuring information over 80 nutrients, can be found under the Food Rating
System Chart.
Health Benefits
Description
History
How to Select and Store
How to Enjoy
Individual Concerns
Nutritional Profile
References
Health Benefits
Cardiovascular Benefits

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. The chart below summarizes some key research findings about
walnuts and heart health:
Cardiovascular AspectWalnut Benefit
Blood Qualitydecreased LDL cholesterol; decreased total cholesterol;
increased gamma-tocopherol; increased omega-3 fatty acids in red blood
cells (alpha-linolenic acid)
Vasomotor Tonedecreased aortic endothelin; improved endothelial cell
function
Risk of Excessive Clottingdecreased maximum platelet aggregation rate;
decreased platelet activation
Risk of Excessive Inflammationdecreased C reactive protein (CRP);
decreased tumor necrosis factor alpha (TNF-a)

Research on the blood pressure benefits of walnuts has been mixed. We suspect
that these mixed results are related to the surprising differences in mineral
composition amongst different varieties of walnuts. Researchers have long been
aware of the relationship between healthy blood pressure and intake of specific
minerals, including potassium, calcium, and magnesium. In multiple studies,
these minerals have a much greater impact on blood pressure than the mineral
sodium (familiar to most people in its sodium chloride form, i.e., everyday
table salt). We've seen studies showing the following ranges for key blood
pressure-regulating minerals in walnuts:
MineralNatural Range Found Amongst Different Walnut Varieties (milligrams
per 100 grams)
Potassium375-500
Calcium13-91
Magnesium189-278

Even though there are valuable amounts of these blood pressure-regulating
minerals in virtually all varieties of walnuts, the ranges above may help
explain why some studies have shown statistically significant benefits from
walnuts on blood pressure while others have not.
Not in question with respect to walnuts and cardiovascular support is their
reliable omega-3 content. Adequate intake of omega-3s, including the
alpha-linolenic acid (ALA) present in walnuts, has repeatedly been shown to help
improve a wide variety of cardiovascular functions, including blood pressure. In
at least one research study, adults have been able to significantly increase
their blood level of ALA with as few as 4 walnuts per day.
Walnuts Help Reduce Problems in Metabolic Syndrome
In the United States, as many as 1 in 4 adults may be eligible for diagnosis
with Metabolic Syndrome (MetS). MetS isn't so much a "disease" as a
constellation of problematic and overlapping metabolic problems including
excessive blood fats (triglycerides), high blood pressure, inadequate HDL
cholesterol, and obesity (as measured by waist circumference, and/or body mass
index). Recent studies have shown that approximately one ounce of walnuts daily
over a period of 2-3 months can help reduce several of these MetS-related
problems. In addition, addition of walnuts to participant diets has also been
shown to decrease "abdominal adiposity"-the technical term for the depositing of
fat around the mid-section. Importantly, the MetS benefits of added walnuts have
been achieved without causing weight gain in any the studies we've seen to date.

Benefits in Treatment of Type 2 Diabetes
Although we think about type 2 diabetes as a problem primarily related to blood
sugar control and insulin metabolism, persons diagnosed with type 2 diabetes
typically have health problems in other related systems, and are at special risk
for cardiovascular problems. An important part of the goal in designing a diet
plan for persons with type 2 diabetes is lowering the risk of future
cardiovascular problems. In this context, consumption of walnuts is establishing
a more and more impressive research track record. Increased flexibility in the
response of the cardiovascular system following meals has been a repeated
finding in research on walnuts. A variety of different measurements on blood
vessel functioning (including their measurement by ultrasound) show a relatively
small amount of daily walnut intake (1-2 ounces) to provide significant benefits
in this area for persons with type 2 diabetes. Better blood fat composition
(including less LDL cholesterol and less total cholesterol) has also been
demonstrated in persons with type 2 diabetes.
Anti-Cancer Benefits
Given the wide variety antioxidant and anti-inflammatory nutrients found in
walnuts, it's not surprising to see research on this tree nut showing measurable
anti-cancer benefits. The antioxidant properties of walnuts help lower risk of
chronic oxidative stress, and the anti-inflammatory properties help lower risk
of chronic inflammation, and it is precisely these two types of risk, that, when
combined, pose the greatest threat for cancer development. Prostate cancer and
breast cancer are the best-studied types of cancer with respect to walnut
intake, and their risk has been found to be reduced by fairly large amounts of
walnut consumption. (Large in this case means approximately 3 ounces per day.)
For prostate cancer, the evidence is somewhat stronger, and more studies have
involved human subjects. For breast cancer, most of the evidence has been based
on studies of rats and mice.
Other Health Benefits
The anti-inflammatory nutrients in walnuts may play a special role in support of
bone health. A recent study has shown that large amounts of walnuts decrease
blood levels of N-telopeptides of type 1 collagen (NTx). These collagen
components provide a good indicator of bone turnover, and their decreased blood
level in response to walnut intake is an indication of better bone stability and
less mineral loss from the bone. "Large amounts" of walnuts (in this study,
actually raw walnuts plus walnut oil) translated into 50% of total dietary fat.
In an everyday diet that provided 2,000 calories and 30% of those calories from
fat, this 50% standard for walnuts would mean about 67 grams of fat from walnuts
or 4 ounces of this tree nut on a daily basis. While this amount is more than
would most people would ordinarily consume, we expect the health benefits of
walnuts for bone health to be demonstrated in future studies at substantially
lower levels of intake.
Walnuts have also produced a good track record in the research as a desirable
food for support of weight loss and for prevention of obesity. That finding
often surprises people because they think of high-fat, high-calorie foods as a
primary contributing factor to obesity and to weight gain. In general,
overconsumption of high-fat, high-calorie foods is a primary contributing factor
to obesity and weight gain. However, obesity has also been clearly identified by
researchers as involving chronic, unwanted inflammation. As discussed earlier in
this Health Benefits section and throughout this walnuts' profile, walnuts are
unique in their collection of anti-inflammatory nutrients. These nutrients
include omega-3 fatty acids; phytonutrients including tannins, phenolic acids,
and flavonoids; quinones like juglone; and other anti-inflammatory
phytonutrients. These anti-inflammatory benefits can overshadow the high-calorie
and high-fat risk posed by walnuts, and that's exactly what they have done in an
increasing number of research studies involving risk and/or treatment of
obesity. While it is definitely possible to overconsume walnuts, most everyday
diets could remain correctly balanced in terms of calories and fat while still
including fairly generous amounts of walnuts (in the range of 1-3 ounces).
A limited (but increasing) number of studies have shown potential health
benefits for walnuts in the area of memory and general thought processes (often
referred to as "cognitive" processes). Thus far, most of the initial research in
this area has involved rats and mice, but we expect to see cognitive benefits of
walnuts for humans becoming a topic of increasing research interest.
A final fascinating aspect of walnuts and their potential health benefits
involves melatonin (MLT). MLT is a widely-active messaging molecule in our
nervous system, and very hormone-like in its regulatory properties. MLT is
critical in the regulation of sleep, daily (circadian) rhythms, light-dark
adjustment, and other processes. It has also been found to be naturally
occurring within walnuts. Average melatonin (MLT) content of walnuts is
approximately 3.6 nanograms (ng) per gram (g), or 102ng/ounce. Other commonly
eaten foods - for example, cherries - have also been found to measurable amounts
of MLT. Researchers are not yet sure how everyday intake of MLT from walnuts is
involved in our health, but several study authors have hypothesized about the
MLT in walnuts as playing an important role (along with other walnut nutrients)
in the anti-cancer benefits of this unusual food.
Description
Walnuts are a delicious way to add extra nutrition, flavor and crunch to a meal.
While walnuts are harvested in December, they are available year round and a
great source of those all-important omega-3 fatty acids.
It is no surprise that the regal and delicious walnut comes from an ornamental
tree that is highly prized for its beauty. The walnut kernel consists of two
bumpy lobes that look like abstract butterflies. The lobes are off white in
color and covered by a thin, light brown skin. They are partially attached to
each other. The kernels are enclosed in round or oblong shells that are brown in
color and very hard.
While there are numerous species of walnut trees, three of the main types of
walnuts consumed are the English (or Persian) walnut, Juglans regia; the black
walnut, Juglans nigra; and the white (or butternut) walnut, Juglans cinerea. The
English walnut is the most popular type in the United States and features a
thinner shell that is easily broken with a nutcracker. The black walnut has
thicker shells that are harder to crack and a much more pungent distinctive
flavor. The white walnut features a sweeter and oilier taste than the other two
types, although it is not as widely available and therefore may be more
difficult to find in the marketplace. Within these basic types of walnuts, there
are dozens of different varieties (also called cultivars). It's not uncommon to
see research studies that evaluate several dozen different cultivars of English
or black walnuts. All types and varieties of walnuts can have unique nutrient
composition. Sometimes within a particular type of walnut - for example, English
walnut - there is a surprising amount of nutritional variety. The bottom line
here is to not to get caught up in thinking that one main type of walnut (for
example, English versus black) is best, but to take advantage of the nutritional
variety offered by walnuts overall.
History
While walnut trees have been cultivated for thousands of years, the different
types have varying origins. The English walnut originated in India and the
regions surrounding the Caspian Sea, hence it is known as the Persian walnut. In
the 4th century AD, the ancient Romans introduced the walnut into many European
countries where it has been grown since. Throughout its history, the walnut tree
has been highly revered; not only does it have a life span that is several times
that of humans, but its uses include food, medicine, shelter, dye and lamp oil.
It is thought that the walnuts grown in North America gained the moniker
"English walnuts," since they were introduced into America via English merchant
ships.
Black walnuts and white walnuts are native to North America, specifically the
Central Mississippi Valley and Appalachian area. They played an important role
in the diets and lifestyles of both the Native American Indians and the early
colonial settlers.
China is presently the largest commercial producer of walnuts in the world, with
about 360,000 metric tons produced per year. The United States is second, with
about 294,000 metric tons of production. Within the U.S., about 90% of all
walnuts are grown in California, particularly within the San Joaquin and
Sacramento Valleys The annual combined walnut output of Iran and Turkey is
approximately the same as the United States, and the Ukraine and Romania are
next in line in terms of total walnut production.
How to Select and Store
When purchasing whole walnuts that have not been shelled choose those that feel
heavy for their size. Their shells should not be cracked, pierced or stained, as
this is oftentimes a sign of mold development on the nutmeat, which renders it
unsafe for consumption.
Shelled walnuts are generally available in prepackaged containers as well as
bulk bins. Just as with any other food that you may purchase in the bulk
section, make sure that the bins containing the walnuts are covered and that the
store has a good product turnover so as to ensure its maximal freshness. Whether
purchasing walnuts in bulk or in a packaged container avoid those that look
rubbery or shriveled. If it is possible to smell the walnuts, do so in order to
ensure that they are not rancid.
Due to their high polyunsaturated fat content, walnuts are extremely perishable
and care should be taken in their storage. Shelled walnuts should be stored in
an airtight container and placed in the refrigerator, where they will keep for
six months, or the freezer, where they will last for one year. Unshelled walnuts
should preferably be stored in the refrigerator, although as long as you keep
them in a cool, dry, dark place they will stay fresh for up to six months.



© 2001-2011 The George Mateljan Foundation