Can mood be used as a highly sensitive indicator of sub-clinical nutrient deficiencies?

Micronutrients function as essential cofactors in all the fundamental biochemical pathways including neurotransmitter synthesis; the brain, with its high metabolic rate and dependence on balanced neurotransmitter synthesis and function, is therefore particularly sensitive to even slight deficiencies. Psychological symptoms, especially negative changes in mood, are probably the very first indications of a deficient dietary intake of micronutrients or absorption problems, particularly amongst the elderly. Such symptoms are generally reversible and positively respond to an improved dietary intake or appropriate supplements, suggesting a causal relationship between deficient micronutrient status and negative psychological symptoms.

Thiamin is the most important ‘mood’ vitamin. Thiamin-deficient cells are unable to use glucose aerobically, which restricts energy availability within the brain. Thiamin is also needed to maintain neurotransmitter function. Experimental deprivation of thiamin rapidly induces feelings of depression and irritability which disappear on supplementation. Studies have confirmed that mood is positively correlated to thiamin status, and that thiamin supplementation also improves mood and cognitive function in subjects who are not thiamin-deficient, according to current definitions. This suggests that current recommended levels for thiamin intake (and possibly other nutrients) may be inadequate for optimal brain function.

Surveys show that up to 50% of people in industrialised societies, particularly the elderly and adolescents, have marginal thiamin intakes because of nutrient-poor, highly refined diets.

Symptoms associated with a chronic thiamin deficiency include:

  • mood swings
  • erratic temper
  • depression
  • anxiety

Other vitamins which influence mood include:

  • Folate
  • Riboflavin
  • Niacin
  • Vitamin B6 and B12
  • Vitamin C.

Depression is the most common manifestation of folate deficiency. Between 15-38 % of adults with depressive disorders show low red blood cell folate levels. Low levels are also associated with a poorer response to some antidepressant drugs. Folate and vitamins B6 and B12 are needed for methylation reactions, which are crucial to the health of brain tissue. An association between loss of cognitive function and inadequate status of these B vitamins has been demonstrated.

Marginal deficiencies of riboflavin and niacin are associated with – emotional instability, fatigue, irritability, anxiety and depression. B6 is a cofactor in the production of serotonin and dopamine, important ‘mood’ neurotransmitters, and supplements can relieve the depression and mood swings associated with Pre-Menstrual Syndrome. B12 deficiency is associated with mild depression and lassitude and vitamin C deficiency with the neuropsychiatric triad of depression, hysteria and hypochondriasis.

Iron, selenium and zinc appear to be the critical mineral determinants of mood. Iron deficiency is one of the most common deficiencies worldwide with –

  • dieters
  • endurance athletes
  • vegetarians
  • menstruating females being most at risk.

Even mild iron deficiency negatively impacts on mood and cognitive function as iron is essential for transporting oxygen to brain cells and neurotransmitter metabolism. Deficiencies of selenium disrupt serotonin, dopamine and adrenaline activity with a concomitant depression of mood. Selenium supplementation reduces feelings of anxiety and depression leading to marked improvements in mood. As many areas in the world have selenium-deficient soils, including the UK, this mineral deficiency is particularly widespread. Mental apathy and depression are associated with zinc deficiency and may be due to its function as a modulator of endogenous opiate-receptor binding in the brain.

Whether we eat a micronutrient-dense diet or a nutritionally inadequate diet has dramatic ramifications on how we feel and increasing evidence suggests that persistently negative moods should definitely alert us to the possibility of sub-clinical micronutrient deficiencies.