“Can Diet Protect Against Kidney Cancer?”
58,000 Americans are diagnosed with kidney
cancer every year, and 13,000 die.
And the numbers have been going up.
Approximately 4% of cases are hereditary,
but what about the other 96%?
The only accepted risk factor has been tobacco
use, but cigarette smoking has been declining.
Nitrosamines are one of the most potent
carcinogens in cigarette smoke.
So much so there’s a concern that
nonsmokers may be inadvertently exposed
through so-called third hand smoke.
See, the risks of tobacco exposure do not
end when the cigarette is extinguished.
Residual smoke particles
can contaminate surfaces.
About 80% of these nitrosamines in secondhand
cigarette smoke stick to room surfaces
and are not removed under
normal ventilation conditions.
That’s why it’s important to only
stay in smoke-free rooms in hotels.
The bottom line is that there is no way to safely
smoke indoors, even if there’s no one else there.
Nitrosamines are considered so toxic
that carcinogens of this strength
in any other consumer product designed for
human consumption would be banned immediately.
If that were the case, they’d have to ban meat.
One hot dog has as many nitrosamines and
nitrosamides as 5 cigarettes, if you do the math.
And these carcinogens are also found in
fresh meat as well: beef, chicken and pork.
So even though smoking
rates have dropped,
perhaps the rise in kidney cancer
over the last few decades may have
something to do with meat consumption.
But would it just be the processed meats,
like bacon, sausage, hot dogs, and cold cuts
that have nitrate and nitrite
additives, or fresh meat as well?
We didn’t know, until now.
The NIH-AARP study is the largest
prospective study on diet and health ever,
with over 4 million years of follow-up, person years
of follow-up — 500,000 people followed for about 9 years.
In addition to examining nitrate and
nitrite intake from processed meat,
they also looked at intake from other
sources such fresh meat, eggs, and dairy.
There are nitrates in vegetables, too.
Should we be worried about those?
No. Nitrite from animal sources – not just processed meats – was associated with an increased risk of kidney cancer.
Total intake of nitrate and nitrite from processed meat
sources was also associated with cancer.
But they found no associations with nitrate
or nitrite intake from plant sources.
But nitrates from processed
meat was associated with cancer.
That’s when they advertise their bacon or lunch meat
is “uncured” – no nitrites or nitrates added,
except for the celery juice they added, which
is just a sneaky way to add nitrites.
See, they ferment the nitrates in celery
to nitrites, then add it to the meat,
a practice even the industry admits may be viewed
as incorrect at best or deceptive at worst.
But that same fermentation of nitrates
to nitrites can happen thanks to bacteria
on our tongue when we eat vegetables.
So why are nitrates and nitrites from vegetables
on our tongue OK, but nitrates and nitrites
from vegetables in meat linked to cancer?
Because the actual carcinogens are not
nitrites but nitrosamines and nitrosamides.
In our stomach to turn nitrites
into nitros-amines, and nitros-amides
we need amines and amides, which
are concentrated in animal products.
And vitamin C and other antioxidants in plant foods block the formation of these carcinogens in our stomach.
That’s why we can safely benefit from the nitrates
in vegetables without the cancer risk.
In fact, some of the highest nitrate
vegetables like arugula, kale, and collards
are associated with decreased
risk of kidney cancer.
The more plants, it appears, the better.
Plant-based diets and fiber-rich diets
are recommended to prevent cancer directly,
as well as chronic conditions associated with kidney cancer, such as obesity, high blood pressure, and diabetes.
So a plant-based diet may help protect
against kidney cancer directly or indirectly.
It’s like sodium intake and kidney cancer.
Sodium intake increases kidney disease risk, but
is that just because it increases blood pressure?
No, it appears the salt is associated with increased
cancer risk even independently of hypertension.
What about plant-based diets?
Turns out the protective association remains even
in people who aren’t obese, with normal blood pressure.
So overall, plant-based and fiber-rich diets appear to do both, decreasing cancer risk both directly and indirectly.