Essential Fatty Acid Deficiency

Why some fats are "essential"

Your body can make most of the fats it needs, but not linoleic acid (LA, an omega-6 fat) or alpha-linolenic acid (ALA, an omega-3 fat). These must come from food. They are building blocks for cell membranes, especially in the skin, brain and eyes, and are converted into longer fats such as arachidonic acid, EPA and DHA, which help regulate inflammation, blood clotting and immunity.

Only a small amount is needed. Linoleic acid making up roughly 1 to 2 percent of daily calories prevents deficiency, which is why EFAD is rare in people eating a varied diet.

Causes and risk factors

• Parenteral nutrition without fat: IV feeding that does not include a lipid emulsion. Deficiency can appear within weeks, faster in infants.
• Fat malabsorption: cystic fibrosis, chronic pancreatitis, short bowel syndrome, severe Crohn's disease, cholestatic liver disease and biliary atresia, and after bariatric surgery.
• Premature and low-birth-weight infants: low fat stores and high needs.
• Severe malnutrition or eating disorders.
• Extremely low-fat diets sustained for long periods.
• Some fish-oil-only lipid emulsions used for liver protection in IV-fed children, which may contain less linoleic acid. Doctors monitor for this.

Symptoms and signs

Skin and hair

• dry, rough, scaly skin, often red, especially on the face, skin folds and limbs
• skin that becomes leathery and cracked
• hair loss or thin, dry hair, and loss of hair color
• poor wound healing

Body-wide effects

• growth failure in infants and children
• increased infections
• low platelet count and easy bruising
• fatty liver
• increased water loss through the skin and thirst

Omega-3 deficiency specifically

Isolated omega-3 deficiency is uncommon. It has been associated with numbness, weakness and vision problems in case reports, and with effects on brain and eye development in infants.

Diagnosis

The standard test is the triene-to-tetraene ratio (Holman index), measured in blood:

• When linoleic acid is lacking, the body makes more of a fat called mead acid (a triene) and less arachidonic acid (a tetraene).
• A ratio above about 0.2 suggests biochemical deficiency, and above about 0.4 is usually associated with clinical signs.

Doctors may also measure the levels of specific fatty acids in blood. The diagnosis is supported by improvement after fat replacement.

Treatment

• Oral or tube feeding: oils rich in linoleic acid, such as sunflower, safflower, soybean, corn or canola oil, added to the diet. Pancreatic enzyme replacement improves absorption in pancreatic insufficiency and cystic fibrosis.
• IV lipid emulsion: for people on parenteral nutrition, adding or adjusting lipid restores levels and prevents recurrence.
• Treating the underlying cause of malabsorption.
• Topical oils such as sunflower oil applied to the skin have been used in infants and may help skin barrier function, but are not a substitute for dietary or IV replacement.

Skin and hair changes usually improve within weeks of adequate fat intake.

Prevention

• Anyone on long-term IV nutrition should receive an appropriate lipid emulsion, with monitoring.
• People with fat malabsorption should be followed by a dietitian, take enzymes as prescribed, and have levels checked if symptoms appear.
• A normal diet including nuts, seeds, vegetable oils, fish and some fat easily prevents deficiency.

Food sources

Frequently asked questions

What are the symptoms of essential fatty acid deficiency?

The main symptoms are dry, scaly, red skin, hair loss, poor wound healing and, in children, poor growth. Others include frequent infections, low platelets and fatty liver. These signs usually appear in people on fat-free IV nutrition or with severe fat malabsorption.

Who gets essential fatty acid deficiency?

It is rare in healthy people. At-risk groups include people on IV nutrition without fat, those with cystic fibrosis, chronic pancreatitis, short bowel syndrome or severe liver disease, premature babies, and people on extreme very-low-fat diets.

How is essential fatty acid deficiency diagnosed?

Doctors measure the triene-to-tetraene ratio in a blood sample. A raised ratio, with symptoms and risk factors, confirms the diagnosis. Levels of specific fatty acids can also be measured.

Can fish oil fix essential fatty acid deficiency?

Fish oil supplies long-chain omega-3 fats but very little linoleic acid, the omega-6 fat most often lacking in classic EFAD. Treatment usually needs oils rich in linoleic acid, such as sunflower or soybean oil, or an IV lipid emulsion.