As mentioned, when vitamin E deficiency occurs, it strikes people with diseases that prevent the absorption of dietary fats and fat-soluble nutrients. These diseases include cystic fibrosis, pancreatitis, and cholestasis (bile-flow obstruction). Bile salts, produced in the liver, are required for the absorption of fats. Cholestasis causes a decrease in the formation of bile salts and the consequent failure of the body to absorb dietary fats. For this reason, this disease may result in vitamin E deficiency. Premature infants may be at risk for vitamin E deficiency because they may be born with low tissue levels of the vitamin, and because they have a poorly developed capacity for absorbing dietary fats. Infants suffering from fat-malabsorption diseases can develop symptoms of vitamin E deficiency by age two. In adults, the onset of a fat-malabsorption disease can provoke vitamin E deficiency after a longer period, as an example, ten years.

Patients with colorectal cancer caused by the so-called Ki-ras mutation have also been shown to absorb less vitamin E from their diet than either normal control subjects or cancer patients without the mutation. The relationship between genetic mutations and dietary factors requires more intensive study.

Vitamin E deficiency in humans results in ataxia (poor muscle coordination with shaky movements), decreased sensation to vibration, lack of reflexes, and paralysis of eye muscles. One particularly severe symptom of vitamin E deficiency is the inability to walk.

Another symptom of early vitamin E deficiency in children with cystic fibrosis is a decline in cognitive function, which results in difficulty with reading and falling behind in other intellectual skills during the elementary school years. Researchers have urged the introduction of neonatal screening in order to offset the potential effects of early vitamin E deficiency.

More recently, the suggestion has been made that vitamin E deficiency may be involved in the development of partial open-angle glaucoma (POAG), an eye disorder whose causes are not fully understood as of the early 2000s. The possibility that POAG is a vitamin-deficiency disorder, however, needs further research.