"Greens, Green Tea, and Nuts Put to the Test for Telomeres"
Telomere length is considered a biomarker of aging:
shorter telomeres are associated with decreased life expectancy
and increased rates of age-related chronic diseases.
Telomere shortening has been shown to be accelerated
by oxidative stress and inflammation.
So since plant foods contain plenty of compounds
with antioxidant and anti-inflammatory properties,
it's plausible that their sustained consumption
might help counteract telomere attrition.
And indeed, if you pull all the best studies on the impact of nutrition
on telomere length, the consumption of vegetables, fruits, beans and nuts
has been associated with positive effects on markers of inflammation
and oxidative stress in parallel with longer telomeres.
By contrast, processed meats, alcoholic and sugar sweetened beverages,
and other foods rich in saturated fats, alcohol, and sugar
are linked to an increase in inflammation
and oxidative stress in parallel with shorter telomeres.
In my last video on telomeres, I featured a randomized controlled trial
showing a whole food, plant-based diet and lifestyle program
could actually lengthen telomeres. Is it just because they cut out the junk?
Those eating the most ultra-processed foods have been found
to have almost twice the odds of having short telomeres.
Maybe it's because they cut out the processed meat,
like bacon, ham, hot dogs, lunchmeat, sausage,
which has been associated with not only cancer and diabetes risk
but shorter telomeres as well, meaning accelerated cellular aging,
though just having something like a steak
was not similarly associated with telomere length.
Processed meat, but not unprocessed red meat,
is associated with shorter telomere length.
This is perhaps due to the particularly high concentrations of glycotoxins,
the advanced glycation end products, as well as carcinogenic nitrosamines
in the processed meat that may promote inflammation and oxidative stress.
The only unprocessed meat associated with shorter telomeres was poultry.
For dairy, it appears to be the milk fat.
A national survey of thousands of Americans
found an association between increased biological aging and
the consumption of high-fat milk.
Even with people just going up like 1% milk fat
(from like 1% milk to 2% milk, low-fat milk to reduced fat milk)
appeared to have more than 4 years of additional biological aging.
We think it's because of the saturated fat, given that saturated fats trigger
an inflammatory response. Not all plant foods are good for you, though.
French fries and potato chip consumption is associated
with shorter telomeres.
Yes, fiber intake goes hand-in-hand with longer telomeres,
as does higher vegetable and fruit consumption,
but that may be trumped by a deep fryer.
What about the consumption of a high fat whole plant food like nuts?
We know higher telomere-building enzyme activity is associated
with a higher dietary antioxidant score,
and botanically, seeds are packed with antioxidants
and by seeds, they mean any food you can put in the ground
and sprout a whole plant, like whole grains, beans, chickpeas, lentils, nuts.
They're naturally enriched in antioxidant compounds
that protect the seed DNA from damage.
Four weeks of Navy beans didn't seem to affect
telomere length, though. What about nuts?
Well, based on how much your telomeres shorten every year,
you can estimate the rate of aging.
In other words, two people can have the same chronological age,
same calendar age, but suffer more or less effective cellular aging.
So, for example, if you smoke a pack a day for a decade,
your cells may age about 3 years faster.
Or, if you drink soda every day,
it's like almost 2 years of additional aging.
So what about nuts?
U.S. adults of the same age would experience almost 2 years less
biologic aging per ounce of nuts and seeds consumed per day,
the amount I recommend in my free Daily Dozen app.
The estimated biologic aging advantage would be nearly 1 year
for each 100 calories of nuts and seeds consumed every day.
The researchers conclude that, clearly, consumption of nuts and seeds
accounts for meaningfully lower levels of biologic aging
in U.S. men and women. But that's just an association.
You don't know if nuts can slow telomere shortening until you put it to the test.
A randomized controlled trial investigating whether the inclusion
of one or two ounces of walnuts a day
for two years would help maintain telomere length,
which normally shortens with age.
In the control group, their telomeres shortened as expected
over those two years, whereas the walnut group telomeres maintained
their length, though the difference didn't reach statistical significance.
Now, that was measuring average telomere length,
and it's probably more telling to look at how long
the shortest telomeres are rather than the average,
and if you do that, look at the percentage of telomeres
that are particularly short,
the walnut group does edge out over the control group.
It's well established that the length of the shortest telomeres is
the key biomarker of the onset of senescence.
The researchers conclude that the inclusion of walnuts
in the regular diet for 2 years tends to delay
leukocyte telomere shortening in older individuals.
A study on pistachio consumption, 2 ounces a day for 4 months,
reduced signs of DNA damage, but did not significantly slow
the rate of telomere shortening.
And this study, which randomized people to eat more mixed nuts,
found a higher risk of telomere shortening in the nut group,
for which the researchers could offer no explanation.
So it's not clear whether nuts help with telomeres or not.
Most supplement intervention studies observed null effects
on telomere length as well, with the exception of green tea.
Thirty-six elderly women were randomly divided into two groups:
exercise alone or exercise with green tea consumption for 5 months,
and a significant boost in telomere length in the green tea group
with no change from the placebo.
Green tea is essentially a green leafy vegetable we dip in hot water.
How about eating green leafy vegetables, in fact the healthiest kind:
cruciferous vegetables like broccoli, cabbage, collards and kale.
They pitted raw versus cooked and found that cooked was better than raw
for reducing DNA damage from a carcinogen,
but raw was more anti-inflammatory. Consequently, to fully exploit
the complexity of the health-promoting potential
of Ethiopian kale, and by extension maybe other cruciferous,
a mix of both raw and cooked vegetables should be part of the diet.
OK, but what about for boosting
the telomere-lengthening age-reversal enzyme?
Raw or cooked. Which do you think?
A short-term dietary intervention showed that cooked but not raw
boosted telomerase activity in as short as five days,
eating one and a quarter cups of this kale a day.
It was thought that you'd need like 4 months of a change
to affect telomeres, but this study provides,
for the first time, evidence that telomerase activity
can respond in a matter of days to a food intervention,
but not just any food, but the healthiest food out there:
cruciferous dark green leafy vegetables.