Food and Behaviour Research

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FAB Research Factsheet 002 - Physical Signs of Fatty Acid Deficiency

Date: 2003

Omega-3 and omega-6 fatty acids are absolutely essential for human life and health, but they must be provided by our diet. They play particularly key roles in brain development and function.

Various physical signs are associated with deficiencies in these essential fatty acids (although all can have other causes).
These include

  • excessive thirst
  • frequent urination
  • rough, dry or scaly skin
  • dry, dull or ‘lifeless’ hair
  • dandruff
  • soft or brittle nails.
Raised, dry 'bumps' on the skin are particularly characteristic. (This is called ‘follicular keratosis’ as it results from a build-up of hard, dry skin around the hair follicles).

Research has shown that these fatty acid deficiency signs are unusually common in people with ADHD, dyslexia and autistic spectrum disorders.(1-7)

They have also been linked with

  • behaviour, learning and health problems in boys with and without an ADHD diagnosis,(4)
  • the severity of reading, spelling and related difficulties in dyslexic children(5)
  • visual, auditory and other features of dyslexia in adults.(6)

This and other evidence has led to treatment trials to find out if supplementing the diet with fatty acids may help in these conditions.

A simple checklist rating scale has been used in many of these studies to assess fatty acid deficiency signs. Across groups, scores have been shown to correlate with blood levels of fatty acids.

However, results from this scale should never be interpreted in isolation, as any reliable diagnosis of fatty acid deficiency would require other information such as blood fatty acid analyses, and ideally a full dietary assessment.

Many other features or clinical signs can sometimes reflect deficiencies or imbalances of omega-3 or omega-6 fatty acids, although research to confirm these links is ongoing. These include:

  • Allergic or ‘atopic’ tendencies (such as eczema, asthma, hayfever etc.)
  • Visual symptoms (such as poor night vision, sensitivity to bright light, or visual disturbances when reading - e.g. letters and words may appear to move, swim or blur on the page)
  • Attentional problems (distractibility, poor concentration and difficulties in working memory)
  • Emotional sensitivity (such as depression, excessive mood swings or undue anxiety)
  • Sleep problems (especially difficulties in settling at night and waking in the morning)

IMPORTANT: Any of these signs can have other causes, so it should never be assumed that fatty acid deficiencies are responsible. Always seek medical attention for any troubling symptoms, and before taking food supplements or making any other major dietary changes. 


    1. Colquhoun, I. and Bunday, S. A lack of essential fatty acids as a possible cause of hyperactivity in children. Medical Hypotheses, 1981; 7: 673-9.
    2. Baker SM. A biochemical approach to the problem of dyslexia. Journal of Learning Disabilities 1985; 18(10): 581 584.
    3. Stevens LJ, Zentall SS. Deck JL, Abate ML, Watkins BA, Lipp SR, Burgess JR. Essential fatty acid metabolism in boys with attention-deficit hyperactivity disorder. American Journal of Clinical Nutrition 1995; 62: 761-8.
    4. Stevens LJ, Zentall SS. Abate ML, Kuczek T, Burgess JR. Omega-3 fatty acids in boys with behaviour, learning, and health problems. Physiol. Behav. 1996; 59(4/5): 915-920.
    5. Richardson AJ, Calvin CM, Clisby C, Schoenheimer DR, Montgomery P, Hall JA, Hebb G, Westwood E, Talcott JB, Stein JF. Fatty acid deficiency signs predict the severity of reading and related difficulties in dyslexic children. Prostaglandins Leukotr Essent Fatty Acids, 2000; 63:69-74.
    6. Taylor KET, Higgins CJ, Calvin CM, Hall JA, Easton T, McDaid AM, Richardson AJ. Dyslexia in adults is associated with clinical signs of fatty acid deficiency. Prostaglandins Leukotr Essent Fatty Acids, 2000; 63:75-78.
    7. Bell JG, Dick JR, MacKinlay EE, Glen ACA, MacDonald DJ, Ross MA, Riordan V, Sargent JR. Red blood cell fatty acid compositions in a patient with autistic spectrum disorder: a characteristic abnormality in neurodevelopmental disorders?. Prostaglandins Leukotrienes and Essential Fatty Acids 2000; 61(2) 21-5.