Are Keto Diets Safe?

Are Keto Diets Safe?

September 12, 2019 100 By William Morgan


“Are Keto Diets Safe?” Given the decades of use
of ketogenic diets to treat certain cases of pediatric epilepsy,
a body of safety data has accumulated. Nutrient deficiencies would
seem to be the obvious issue. Inadequate intake of 17 micronutrients
—vitamins and minerals— has been documented in those
on strict ketogenic diet. Dieting is a particularly
important time to make sure you’re meeting all your
essential nutrient requirements, since you may be
taking in less food. Ketogenic diets tend to be
so nutritionally vacuous that one assessment estimated
that to get a sufficient daily intake of all
essential vitamins and minerals you’d have to eat more than
37,000 calories a day. That’s one of the advantages
of more plant-based approaches. As the editor-in-chief of the Journal of the American
Dietetic Association put it: “What could be more nutrient
dense than a vegetarian diet?” Choosing a healthy diet may be easier than sticking 50 sticks
of butter in your coffee. And we’re not talking about just
not reaching your daily allowances. Children have gotten
scurvy on ketogenic diets, and some have even died
from selenium deficiency (which can cause
sudden cardiac death). The vitamin and mineral deficiencies
can be solved with supplements, but what about the
paucity of prebiotics, the dozens of types of
fiber and resistant starches found concentrated in
whole grains and beans that you’d be missing out on? Not surprisingly, constipation
is very common on keto diets, but as I reviewed before, starving
our microbial self of prebiotics can have a whole array
of negative consequences. Ketogenic diets have
been shown to reduce the richness and diversity
of our gut flora. Microbiome changes can be
detected within 24 hours of switching to a
high-fat, low-fiber diet. The lack of fiber starves
our good gut bacteria, but we used to think dietary fat itself was nearly all
absorbed in the small intestine. But based on studies
using radioactive tracers, we now know that about
7% of the saturated fat in a fat-rich meal can
make it down to the colon, which may result in detrimental
changes in our gut microbiome, weight gain, increased leaky gut,
pro-inflammatory changes. For example, a drop in
beneficial bifidobacteria and a decrease in overall
short-chain fatty acid production, both of which would be expected to increase the risk of
gastrointestinal disorders. OK, but striking at
the heart of the matter, what might all that saturated
fat be doing to our heart? If you look at low-carbohydrate
diets and all-cause mortality, those who eat lower-carb diets
suffer a significantly higher risk of all-cause mortality,
meaning they live, on average, significantly shorter lives. From a heart disease
perspective, though, it matters if it’s an
animal fat or plant fat. Based on the famous Harvard cohorts,
eating more of an animal-based low-carb diet was associated
with higher death rates from cardiovascular disease—
a 50 percent higher risk of dying from a heart
attack or stroke— but no such association was found for lower-carb diets
based on plant sources. And it wasn’t just Harvard. Low-carbohydrate dietary patterns
favoring animal protein and fat, from sources such as
red meat and chicken, were associated with
higher mortality; whereas those favoring
plant protein and fat, from things like vegetables, nuts,
peanut butter, whole grains, was associated with lower mortality. Cholesterol production
in the body is directly correlated to body weight. Every pound of weight
loss by nearly any means is associated with about
a one-point drop in cholesterol levels in the blood. But put people on very
low-carb ketogenic diets and the beneficial effect
on LDL bad cholesterol is blunted or even
completely neutralized. Counterbalancing changes
in LDL size or HDL (what we used to think
of as good cholesterol) are not considered sufficient
to offset this risk. You don’t have to wait until
cholesterol builds up in your arteries, though,
to have adverse effects. Within 3 hours of eating a
meal high in saturated fat you can see a significant
impairment of artery function. Even with a dozen
pounds of weight loss, artery function worsens
on a ketogenic diet which appears to be the case
with low-carb diets in general. So, bad for the gut,
bad for the heart, but is it bad to the bone? We’ll find out next.