What happens if we don’t get enough proteins?

What happens if we don’t get enough proteins?


We have already encountered a few situations
that may create short-term alterations of our protein balance: for example if we skip
a couple of meals, fast for a whole day, perform strenuous resistance training to the point
of depleting our glycogen stores, then we may have to use some of our muscle proteins
to maintain blood glucose. However, when we talk about protein malnutrition
we refer to a long-term deficiency in protein intake. In our rich, post-industrialized countries,
long-term protein deficiency is not a common problem because we already eat more than what
is required so we are generally safe and even if we go on weird diets, weight-loss diets,
unbalanced eating patterns, we may have deficiencies of vitamins and minerals but we will still
have enough proteins in the long term. There are however some segments of the population
that are more at risk for protein deficiency: people living in poverty, for a variety of
reasons including the fact that high-quality protein food tends to be the most expensive,
but also a general lack of nutrition education. The elderly, again in part for economic issues,
but also – especially if they live alone they may be less hungry, or not motivated to eat,
to cook for themselves, maybe they have trouble chewing or swallowing, their taste is different,
so they may not enjoy eating and therefore not have adequate calories and proteins. Alcoholism is a risk factor, alcohol is not
a nutrient but it provides a lot of calories, and it also suppresses appetite, so these
people are often not hungry and they don’t eat enough, missing a bunch of nutrients including
proteins. Eating disorders, especially anorexia nervosa
carries a risk for protein malnutrition, together with everything else that we already know. And then hospitalization, because remember
when you are ill or recovering your protein needs can be way higher, but diet is not always
the first concern of the medical team, and so the patient may not be getting enough proteins. Long-term protein deficiency is a big problem
in many developing countries. And here the problem is twofold. Food is often scarce and of poor protein quality,
since diets are mostly cereal-based. But at the same time, protein needs are also
higher than average to fight disease and infections, often because of food safety issues, contaminated
food and water, undercooked food, or badly preserved food, leading to bacterial, fungal
and parasitic infections. And children are especially at risk for this,
because they already need more proteins for growth, are they are more vulnerable to infections. In most cases, if you are not getting enough
proteins, you are also not getting enough food in general, so not enough calories as
well, and so we refer to this problem as protein-energy malnutrition. The consequences of protein deficiency are
impaired or stunted growth, as indicated by height and weight that are not adequate for
age, and the brain will not be able to fully develop leading to mental retardation that
can sometimes be irreversible. But protein deficiency is a problem for adults
as well. Protein turnover slows down and the person
is not be able to carry on with all the structural and regulatory functions of proteins. Proteins are stolen from the lean mass to
make glucose and energy, leading to muscle wasting and increasing weakness. Inadequate tissue repair leads to organ damage. Impaired immunity leads to an increasing inability
to fight infections, which may very well result in death. The tip of the iceberg of protein malnutrition
are two conditions that are kwashiorkor and marasmus. Kwashiorkor is primarily a disease of protein
deficiency. Protein is not enough, although you may still
be getting enough energy, generally from a diet that is based on grains. Kwashiorkor is a world from Ghana that means
“the disease that a child gets when the next child is born”, what happens is that
the older child switches from breastfeeding to a cereal diet, that is likely inadequate
in proteins. If this is combined with a pre-existing infection,
which further raises the need for protein, then the child is definitely not getting enough
protein. He may still have some fat tissue, some muscle,
but the characteristic sign of kwashiorkor is the swollen abdomen, which is definitely
not abdominal fat, but it’s fluid building up in the abdominal region, a condition known
as ascites. We already know how albumin in the bloodstream
maintains fluid balance: if plasma protein is low, then the osmotic pressure to recall
fluids back into the circulation is too weak, and fluids start leaking and building up in
the interstitial space, causing edema. You can see this boy has edema in his feet
and leg also, but the same happens in his abdomen as well. Hepatic steatosis, or fat liver, further contributes
to the dramatic abdominal swelling. You know the liver can make lipids starting
from carbohydrates, but then to send them around to muscle cells it has to package them
into the lipoproteins. But if it doesn’t have proteins, it cannot
make the lipoproteins, and so these lipids will never be able to even leave the liver,
which will start accumulating them. Marasmus is a full protein AND energy deficiency. So here you are not just not getting enough
proteins, but also not enough lipids, not enough carbs, not enough anything, you are
starving. This leads to complete muscle wasting and
organ damage, a complete depletion of adipose stores, bone loss and a general wasting of
body tissues. All that’s left is basically skin and bones. Most metabolic processes will slow down or
completely stop. Growth is severely stunted. And there is a dramatically higher susceptibility
to infection and disease, and death resulting from these infections which the body is not
strong enough to fight.