What Are the Effects of a Fat Deficiency in Humans?

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Although a fat deficiency in the United States is rare, there are fatty acids that are essential to obtain in the diet. If you are not eating certain foods, you could be at risk for a fatty acid deficiency.
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Although a fat deficiency in the United States is rare, there are fatty acids that are essential to obtain in the diet. If you are not eating certain foods, you could be at risk for a fatty acid deficiency. Omega-6 and omega-3 fatty acids are especially essential.

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Essential fatty acid deficiency can cause skin conditions such as rash and dry skin, vision problems and slow wound healing.

The Linus Pauling Institute explains that humans can make many saturated and some monounsaturated fatty acids in the body. Still, when it comes to omega-6 and omega-3 fatty acids, we need to consume them in our diet. Humans lack the enzymes necessary to make these essential fatty acids (EFAs) ourselves.

Two types of omega-3 fatty acids called DHA and EPA are difficult for humans to synthesize out of the parent form, ALA. Since the conversion rate is so low, scientists also say that getting these polyunsaturated fatty acids (PUFAs), DHA and EPA, directly from food sources, is also essential.

Read more: Your Ultimate Guide to Fats and Why Your Diet Needs Them

Why Are Fatty Acids Important?

Omega-3 and omega-6 polyunsaturated fatty acids are an integral part of cell membrane structures, says the Linus Pauling Institute. They affect how the cell membranes function in a variety of ways such as fluidity, permeability and enzyme activity. What's more is that getting enough of these omega-3 fatty acids in your diet plays a large roll in how many red blood cells (immune cells) you have, as well as other vital cell tissue in the body.

When it comes to DHA, getting enough is most important for your brain and eye health. These polyunsaturated fatty acids help prevent fat deficiency and improve your vision and nervous system function. Getting enough is especially important during pregnancy when the fetus is developing eye cells. A DHA fat deficiency in the pregnant mother during this time can cause permanent vision damage.

Nervous system development is also dependent on omega-3 and omega-6 fatty acids. The gray matter part of the brain — which, according to the U.S. National Library of Medicine, is the part of the brain that contains the cell bodies of neurons — is made up of a large amount of polyunsaturated fatty acids. These PUFAs are critical to obtain through the diet for fetal and infant brain and nervous system growth and development.

Another critical role that essential fatty acids play is in the immune system and inflammatory response. The Linus Pauling Institute explains that oxylipins, derived from PUFAs, are powerful chemical messengers that help the body respond to situations requiring the immune system or inflammatory action.

PUFAs are also significant in their role in gene expression by increasing or decreasing gene transcription — the first step in gene expression. They help to regulate the genes responsible for inflammation.

Keeping omega-6 and omega-3 levels balanced is also vital. The U.S. Department of Health and Human Services says that although a specific optimal ratio is not known, making sure to get both in your diet could help prevent cancer, cardiovascular disease as well as a variety of other chronic diseases.

Read more: Is Eating Fatty Food Actually Bad for Me?

What Happens With Fat Deficiency?

The Linus Pauling Institute lists symptoms of fats being too low, particularly essential fatty acid deficiency:

  • Dry, scaly rash
  • Frequent infections
  • Slow wound healing
  • Growth delay in infants and children

If no fatty acids are present in the diet, biochemical signs of fat deficiency show in seven to 10 days, the same is seen in people with chronic problems absorbing fat and those with cystic fibrosis. Although extreme omega-3 deficiency is rare, a low intake can cause cognitive decline and prevent proper cognitive development. Other positive outcomes of obtaining enough EFAs are:

A fat deficiency of EFAs can also contribute to a higher risk of coronary heart disease, according to an October 2014 analysis in Circulation. A 15 percent lower risk of coronary heart disease events and a 21 percent lower risk of death from coronary heart disease were associated with proper amounts of the polyunsaturated acid, linoleic acid.

The May 2019 study further showed that by replacing 5 percent of daily saturated fatty acid energy with linoleic acid resulted in a 9 percent lowered risk of coronary events and a 13 percent lower risk of death due to ischemic events. Another review published in the May 2019 issue of Circulation found that those with higher levels of linoleic acid had a 23 percent lower risk of cardiovascular mortality.

Other significant risks of essential fat deficiency include a higher risk of metabolic syndrome, more chance of developing dementia and Alzheimer's disease as well as faster decline if you do develop it. A higher chance of developing non-alcoholic fatty liver disease and depression are also risks of low EFA intake.

What Foods Have EFAs?

Essential fatty acids are present in both plant and animal sources. Plant sources have alpha-linoleic-acid (ALA) and linoleic acid, and animal sources contain EPA and DHA. Good food sources of ALA are:

  • Soybean oil
  • Flaxseed
  • Chia seeds
  • Canola oil
  • Walnuts
  • Corn oil
  • Safflower oil
  • Sunflower seeds

The best sources of EPA and DHA come from cold-water fatty fish, says the Linus Pauling Institute. Good examples are:

  • Tuna
  • Herring
  • Mackerel
  • Salmon
  • Sardines
  • Oysters
  • Trout

Read more: 5 Omega-3-Packed Recipes That Aren't Fish

What’s the Recommended EFA Amount?

The amount of essential fatty acids recommended depends on gender and age. According to the Linus Pauling Institute, for omega-6 fatty acid intake, approximately 12 grams per day for adult females and 17 grams per day for adult males is plenty. Seven to 10 grams per day for children is recommended. Omega-3 intakes are 1.1 grams for females, 1.6 grams for males and 0.5 to 1 gram per day for children.

An April 2014 analysis in the Nutrition Journal found that U.S. adults are not getting enough fish and omega-3 fatty acids in their diet. Two servings per week of oily fish at minimum is recommended, providing 400 to 500 grams of EPA and DHA. Although mercury is a contaminant known to be in fish, the benefits of consuming fish outweigh the risks, even for pregnant women, according to an April 2015 article published in the British Journal of Nutrition.

Some Other Important Fat Facts

The 2015-2020 Dietary Guidelines for Americans, eighth edition, recommend the following:

  • Consume less than 10 percent of calories per day from saturated fats.
  • Consume 27 grams per day of oils.
  • Consume 8 ounces per week of seafood.
  • Consume 5 ounces per week of nuts and seeds.

Note that oils should replace solid fats (typically saturated fats) in the diet, not be added on top of them. Oils provide essential fatty acids and vitamin E. These oils can be used for cooking or eat naturally occurring oils found in olives, avocados and fish. Dietary fats help you absorb the fat-soluble vitamins A, D, E and K.

Read more: 18 Fat-Rich Foods That Are Good For You

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