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Certain Fruits May Be Linked to a Lower Risk of Type 2
Diabetes
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There’s compelling evidence supporting the
notion that high-fructose diets are responsible for most chronic disease;
insulin resistance, type 2 diabetes and obesity in particular
Many fruits are very high in fructose, up to 50X the sugar that most of the
fruits our ancestors were exposed to due to consistent hybridization over the
past century for sweetness
Therefore most fruits are best limited or avoided if you have insulin/leptin
resistance as determined by struggling with your weight, or, diabetes,
hypertension, heart disease or cancer
According to a new study, certain kinds of whole fruits—particularly
blueberries, grapes, prunes and apples—may reduce your risk of type 2 diabetes
Consumption of fruit juices, on the other hand, was found to have greater risk.
Those who drank one or more servings of fruit juice each day had a 21 percent
higher risk for type 2 diabetes compared to the others
I believe most will benefit from restricting their fructose to 25 grams a day;
and as little as 15 grams a day if you’re diabetic or have chronic health
issues. This includes fructose from whole fruits
By Dr. Mercola
You’re probably well-familiarized with my
controversial stance on fructose. Compelling evidence shows that fructose
is, by far, more harmful to your health than other sugars—especially when
it’s removed from whole fruits and highly processed and genetically
modified, such as high fructose corn syrup (HFCS) found in most processed
foods.
I’ve also, as a general rule, warned you of eating too much fruit, as many
fruits can be quite high in fructose.
This has caused some confusion and consternation among many readers, as
fruit has long been promoted as an important part of a healthy diet. That
said, there are considerations to
take into account when it comes to fruit consumption—some of which are
dependent on your individual and specific circumstances.
I will seek to clarify some of these points here. I believe there’s more
than compelling evidence supporting the concept that high-fructose diets are
a primary factor that is responsible for most chronic disease; insulin
resistance, type 2 diabetes and obesity in those who eat a highly processed
food diet..
I’ve long urged those struggling with these health issues, or who have
hypertension, heart disease or cancer, to pay extra-careful attention to the
fructose content of whole fruit in addition to other sources of fructose.
Now, recent research indicates that some fruits may in fact be protective against
type 2 diabetes.
Continued down....
Articles
Can You Reduce Your Risk of Type 2 Diabetes with Your Fruit
Choices?
According to a new analysis of three
cohort studies, published in the British Medical Journal,1 whole
fruits—particularly blueberries, grapes, prunes and apples—may in fact
reduce your risk of type 2 diabetes. Conversely, consumption of fruit juices
was associated with greater risk. According to senior author Qi Sun, an
assistant professor in the department of nutrition at the Harvard School of
Public Health:2
"While fruits are recommended as a measure for
diabetes prevention, previous studies have found mixed results for total
fruit consumption. Our findings provide novel evidence suggesting that
certain fruits may be especially beneficial for lowering diabetes risk."
The researchers analyzed the dietary records of nearly 190,000 people who
had participated in three studies from 1984 to 2008. None of the
participants were diagnosed with diabetes, cardiovascular disease or cancer
at the outset of the studies.
They found that those who ate blueberries, grapes and apples at least twice
a week were up to 23 percent less likely to develop type 2 diabetes,
compared to those who ate these fruits once a month or less.
I find this quite surprising as, grapes and apples are particularly high in
fructose (as you can see in the chart below). It’s unclear why the authors
observed this benefit here but it’s likely that the phytonutrients found in
the apples and grapes are more than compensate for any potential fructose
toxicity.
Antioxidants and other phytonutrients combat inflammation, which is a
hallmark of diabetes and most other chronic disease. Similarly, blueberries,
which are much lower in fructose, have in other studies also been found to
be of benefit for diabetics primarily due to their high antioxidant content.
One antioxidant in particular, called quercetin, could potentially help
explain some of the results. Apples for example, while high in fructose,
contains this flavonoid, which actually blocks some of the fructose
metabolism according to expert Dr. Richard Johnson. If you haven't done so
yet, I recommend viewing my "What
Are Apples Good For?" information page for a listing of even more
benefits of apples.
Red grapes, plums and many different berries, including blueberries. also
contain quercetin. I have scheduled an interview with Dr. Johnson, in which
we’ll delve into this at greater depth. So keep your eye out for that
interview, which should be out before year end, if you want to learn more.
Don’t Be Fooled By Fruit Juices and Smoothies
In comparison, the featured study found
that those who drank one or more servings of fruit juice each
day had a 21 percent higher risk
for type 2 diabetes compared to the others. This is a really important
point, and I’ve often highlighted the potential harm of drinking fruit
juices.
You’re simply getting FAR too much fructose, not to mention the rarely
mentionedmethanol
toxicity in any preserved
juice. Furthermore, while whole fruits do contain
fructose, they’re also rich in fiber, antioxidants, and a vast array of
health-promoting phytochemicals.
Fruit juices, especially not pasteurized,
commercially-available fruit juices have virtually none of these
phytonutrients. The fiber in the whole fruits also plays a large in
protecting you from a rapid and exaggerated rise in blood sugar. The fiber
slows the rate at which sugar is absorbed into your bloodstream.
This also applies to fruit smoothies, which are often touted as a convenient
strategy to boost your fruit and veggie intake. Unfortunately, they too
contain excessive amounts of fructose, and perhaps even added sugars on top
of that. As reported by the Guardian:3
“In the UK, Coca-Cola owns Innocent Smoothies while PepsiCo has
Tropicana. Launching Tropicana smoothies in 2008, Pepsi's sales pitch
was that the drink would help the nation to reach its five a day fruit
and vegetable target.
"Smoothies are one of the easiest ways to boost daily fruit intake as
each 250ml portion contains the equivalent of two fruit portions," it
said at the time.
However, Popkin [professor at the department of nutrition at
the University of North Carolina] says
the five a day advice needs to change. Drink vegetable juice, he says,
but not fruit juice. "Think of eating one orange or two and getting
filled," he said. "Now think of drinking a smoothie with six oranges and
two hours later it does not affect how much you eat.
The entire literature shows that we feel full
from drinking beverages like smoothies but it does not affect our
overall food intake, whereas eating an orange does. So pulped-up
smoothies do nothing good for us but do give us the same amount of sugar
as four to six oranges or a large coke. It is deceiving."
Revisiting Fruit Consumption
I recently interviewed Dr. Brian Clement
of the Hippocrates Institute, where they teach raw veganism. Interestingly
enough, they also strongly advise most people avoid eating fruits. One of
the primary reasons for their stand against fruits is because of the
hybridization of fruits, which has made them up to 50 times sweeter than
their ancient ancestors. Many fruits have been selectively and purposely
bred for increased sweetness, which has also resulted in reduced
phytochemical content. This hybridization and subsequent deterioration of
healthful nutrition in whole foods was highlighted in a New York Times4 article
published earlier this summer.
The dramatically increased fructose content of otherwise natural and
“wholesome” fruits is the primary problem with high fruit consumption, and
this is why I’m leery of very high-fruit diets.
Many of the most beneficial phytonutrients found in fruits actually have a
bitter, sour or astringent taste, but to satisfy the palate, farmers have,
throughout time, opted to selectively breed the sweetest varieties. Today,
the “candification” of food is being taken to a whole new level, and if
you’re stuck on the idea that all fruit
is good for you, you may end up in a real metabolic pickle... For example,
according to a recent report in the Los Angeles Times,5 one
fruit breeder has created a type of grape called the Cotton Candy grape,
which is absolutely bound to be just as problematic as any other junk food!
“Bite into one of these green globes and the taste triggers the
unmistakable sensation of eating a puffy, pink ball of spun sugar,” the
article states. “By
marrying select traits across thousands of nameless trial grapes, Cain
and other breeders have developed patented varieties that pack enough
sugar they may as well be Skittles on the vine. That's no accident.
"We're competing against candy bars and cookies," said Cain, 62, a
former scientist at the US Department of Agriculture who now heads
research at privately owned International Fruit Genetics in
Bakersfield.”
In light of these issues, let me restate my recommendations on fruit and
fructose consumption as simply as possible:
-
If you’re insulin- or leptin resistant (are overweight, diabetic,
hypertensive, or have high cholesterol), which includes about 80 percent
of Americans, then it would be advisable for you to limit your fruit
intake. As a general rule, I recommend limiting your fructose intake to
a maximum of 15 grams of fructose per day from ALL sources, including whole
fruit.
-
If you are not insulin/leptin
resistant, (are normal weight without diabetes, hypertension or high
cholesterol) and regularly
engage in strenuous physical activity or manual labor, then higher
fructose intake is unlikely to cause any health problems. In this case,
you can probably eat more fruit without giving it much thought.
-
However if you are in category two above you might benefit from a
further refinement. Fruit will still increase your blood sugar and many
experts believe this will increase your protein glycosylation. So my
approach is to consume the fruit typically after a workout as your body
will use the sugar as fuel rather than raise your blood sugar.
-
Additionally ,if you’re an endurance athlete, you can probably get away
with eating fairly large amounts of fruits, since your body will use
most of the glucose during exercise,
so it won’t be stored as fat. (That said, I still believe athletes would
be well-advised to consider becoming fat
adapted rather than
relying on quick sugars. This is outside the scope of this article,
however, so for more information, please see this previous article).
-
If you’re still unsure
of just how stringent you need to be, get your uric acid levels checked,
and use that as a guide. I’ll review this in more detail in the section
below.
Using Your Uric Acid Level as a Marker for Fructose Toxicity
I’ve previously interviewed Dr. Richard Johnson
about his research into the health dangers of fructose, specifically how
fructose causes high blood pressure, obesity, and diabetes, revealed in his
excellent book, The Sugar Fix.
He’s also the chief of the division of kidney disease and hypertension at
the University of Colorado.
Dr. Johnson’s research suggests that your uric
acid levels can be
effectively used as a marker for fructose toxicity; meaning, an indicator of
just how significant of an impact fructose has on your individual body and
health. As such, it can help you gauge justhow careful you
need to be in your food selections.
According to the latest research in this area, the safest range of uric acid
is between 3 and 5.5 milligrams per deciliter (mg/dl), and there appears to
be a steady relationship between uric acid levels and blood pressure and
cardiovascular risk, even down to the range of 3 to 4 mg/dl. What this means
is that if you have a level of 4 mg/dl for men and 3.5 mg/dl for women, you
probably are at a very low risk for fructose toxicity and can be more
liberal with the fructose limits given above. The higher your uric acid
though, the more you need to limit, or even avoid, fructose until your uric
acid level normalizes.
Using this biochemical marker, I came to realize that I am particularly
sensitive to fructose, and that it’s best for me, personally, to keep my
fructose consumption as low as possible. This is most likely due to genetics
and would explain why most of my paternal relatives have, or have died from,
diabetes. That side of the family is probably particularly sensitive to
fructose. Dr. Johnson has developed a program to help people optimize their
uric acid levels, and the key step in this program is complete
elimination of fructose, until your levels are within the ideal range
of 3-5.5 mg/dl.
Helpful Fructose Chart for Common Fruits
Again, most people will need to limit your
fructose to 25 grams of fructose per day from all sources,
or less, while endurance athletes could have more. The chart below is
excerpted from Dr. Johnson’s book, The
Sugar Fix, which contains more details on the fructose content of
common foods. His latest book, The
Fat Switch, also gives further details on HOW fructose impacts your
body, contributing to excess weight and chronic health problems.
Fruit |
Serving Size |
Grams of Fructose |
Limes |
1 medium |
0 |
Lemons |
1 medium |
0.6 |
Cranberries |
1 cup |
0.7 |
Passion fruit |
1 medium |
0.9 |
Prune |
1 medium |
1.2 |
Apricot |
1 medium |
1.3 |
Guava |
2 medium |
2.2 |
Date (Deglet Noor style) |
1 medium |
2.6 |
Cantaloupe |
1/8 of med. melon |
2.8 |
Raspberries |
1 cup |
3.0 |
Clementine |
1 medium |
3.4 |
Kiwifruit |
1 medium |
3.4 |
Blackberries |
1 cup |
3.5 |
Star fruit |
1 medium |
3.6 |
Cherries, sweet |
10 |
3.8 |
Strawberries |
1 cup |
3.8 |
Cherries, sour |
1 cup |
4.0 |
Pineapple |
1 slice
(3.5" x .75") |
4.0 |
Grapefruit, pink or red |
1/2 medium |
4.3 |
|
Fruit |
Serving Size |
Grams of Fructose |
Boysenberries |
1 cup |
4.6 |
Tangerine/mandarin orange |
1 medium |
4.8 |
Nectarine |
1 medium |
5.4 |
Peach |
1 medium |
5.9 |
Orange (navel) |
1 medium |
6.1 |
Papaya |
1/2 medium |
6.3 |
Honeydew |
1/8 of med. melon |
6.7 |
Banana |
1 medium |
7.1 |
Blueberries |
1 cup |
7.4 |
Date (Medjool) |
1 medium |
7.7 |
Apple (composite) |
1 medium |
9.5 |
Persimmon |
1 medium |
10.6 |
Watermelon |
1/16 med. melon |
11.3 |
Pear |
1 medium |
11.8 |
Raisins |
1/4 cup |
12.3 |
Grapes, seedless (green or red) |
1 cup |
12.4 |
Mango |
1/2 medium |
16.2 |
Apricots, dried |
1 cup |
16.4 |
Figs, dried |
1 cup |
23.0 |
|
What About Fruit Juices?
One of the profound highlights revealed in the
featured study was the dramatic difference in health outcome between eating
whole fruits versus drinking fruit juice. It’s important to realize that
fruit juice typically
contains very high
concentrations of fructose, which will cause your insulin to spike and may
counter the benefits of the antioxidants.
Previous studies have already clearly demonstrated that drinking large
amounts of fruit
juice dramatically increases
your risk of obesity. Children are at particular risk here, since so many
children are given juice whenever they’re thirsty instead of plain water.
For example, research has revealed that 3- and 4-year-olds who carry extra
weight and drink just one to two sweet drinks a day double their risk of
becoming seriously overweight just one year later.
Furthermore, when buying commercial fruit juice, you need to check the
label, as the majority of fruit juices contain high fructose corn syrup and
artificial flavors in addition to concentrated fruit juice. That said, even
freshly squeezed fruit juice can contain about eight full teaspoons of
fructose per eight-ounce glass! So, as a general rule, it’s wise for most to
severely restrict your consumption of fruit juice, especially if your uric
acid is above the ideals recommended. Also, if you suffer from type 2
diabetes, hypertension, heart disease or cancer, you’d be best off avoiding
fruit juices altogether until you’ve normalized your uric acid and insulin
levels.
Within Certain Limits, Fruit is OK for Most People
Going back to the issue of genetic variability,
it seems that some people may be able to process fructose more efficiently,
and the key to assess this susceptibility to fructose damage lies in
evaluating your uric acid levels. I believe this is an ideal way for most
people to personalize the
recommendations on fructose intake.
Aside from that, I believe most will benefit from restricting their fructose
to 25 grams a day; and as little as 15 grams a day if you’re diabetic or
have chronic health issues. This includes fructose
from whole fruits. So I’m not advocating fruit avoidance for everyone; I’m
simply placing fruit in the category of a fructose-rich food that needs to
be included when
you’re calculating your fructose intake.
If you choose low-fructose fruits, such as blueberries, you can eat more of
it than if you choose a fruit high in fructose. Other low-fructose fruits
include fresh apricots, lemons, limes, passion fruit, plums and raspberries.
Also remember that avocado is actually a fruit too. It’s very low in
fructose, and high in healthful fat, making it an excellent choice.
Endurance athletes and others who engage in strenuous activities and who are
neither overweight nor have chronic health issues probably do not need to
concern themselves too much with their fruit consumption however.
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