The connections between nutrition and fatigue are many. Bill Sardi reports on the lastest state of the science.
Fatigue is a common symptom reported by up to 20 per cent of patients seeking care from primary care physicians in the US.1 According to Melvin R. Werbach, MD, a faculty member at the University of California at Los Angeles, patients should start by modifying their diets: avoid simple carbohydrates, caffeine, and sugar, and selectively use food supplements to overcome that too-common run-down feeling.2
Several common origins of fatigue may be iron or B-vitamin deficiency anaemias (red blood cell shortage); iron overload; or a shortage of nutritional co-factors involved in the production of cells' energy molecules, adenosine triphosphate (ATP).
The nutritional factors contributing to fatigue vary with age and gender. Menstruating women are more likely to feel tired because of an iron deficiency, whereas men 40 years and older are more likely to tire from iron overload.3 Poor absorption of vitamin B12 causes a high percentage of older adults to feel tired. Post-surgical patients may tire easily from blood loss (anaemia).4
Iron In The Balance
Both low and high iron levels may induce fatigue. In a European study of 6,000 people, researchers detected iron-deficiency anaemia amongst 6 per cent of the females and only .5 per cent of males, whereas they found iron overload amongst 1.8 per cent of the study population.5
Low iron levels are a common reason for women feeling tired.6 While anaemia may be understandably common among menstruating females—as prevalent as one in five women—only 2 per cent of males are anaemic. But the anaemia rate of adults older than 85 may be similarly high—ranging from 17 to 28 per cent. Anaemia in this population not only increases symptoms of fatigue but is also associated with higher mortality rates.7
Anaemia has many underlying causes. Because the body stores 80 per cent of its iron in red blood cells, blood loss can cause fatigue. Blood donation, malabsorption, menstruation, peptic ulcers and pregnancy are common causes of iron shortage and subsequent fatigue.8
Iron overload is the flip side of iron-linked fatigue. In a 1997 study in France, 42 per cent of 176 men and 64 per cent of 176 women with iron overload reported fatigue.9 In a state of iron overload, fatigue is often accompanied by arthritis, diabetes, infertility, male impotence, skin pigmentation, and liver or heart disease.10 The only reliable way to distinguish iron overload from anaemia is to conduct a blood test that measures the amount of iron being transported back to the liver, the percentage of saturation, and serum iron and ferretin levels.11
Researchers suggest high-dose iron tablets be sold by prescription because many consumers mistakenly take iron supplements when they feel fatigued.12 Because iron tablets may cause nausea and increase the risk of infection, researchers have proposed supplementary vitamin C, which increases iron absorption from foods. Plant foods contain poorly absorbed iron, whereas meat provides highly absorbed heme iron. The relatively high vitamin C content of plant foods increases iron absorption and prevents anaemia in vegetarians.13 Vitamin A and vitamin B2 (riboflavin) enhance the efficacy of iron supplementation.14
Because fatigue often demands a quick remedy, food supplements are often employed rather than foods alone.
- Vitamin B12 deficiency may cause fatigue. It may initially be accompanied by indigestion or diarrhea and by short-term memory loss; sore tongue; and tingling, burning or numb feet in advanced stages. This deficiency disease is also called pernicious anaemia.15 Deficiency symptoms also include confusion, loss of vibration sensation, and walking and balance disturbances.16
Results from a recent study conducted by the US Department of Agriculture indicates nearly two-fifths of the US adult population has marginal vitamin B12 levels.17 B12 deficiency results in fewer but larger red blood cells.
- Coenzyme Q10 is vital for the production of cellular energy (ATP) and heart-pumping action.18 Heart failure is likely to produce symptoms of fatigue and swelling, symptoms that were evident in 37 per cent and 66 per cent, respectively, of 753 veterans treated for heart failure in a recent study.19
The onset of a heart attack may be preceded by unusual tiredness, which may indicate a need for more Co-Q10.20 Doses of 100-255mg/day supplemental Co-Q10 have successfully reversed heart failure.21 Patients who took 200mg/day Co-Q10 showed increased heart-pumping action in one study.22 The daily provision of 200mg Co-Q10 produced universal relief from fatigue and shortness of breath among seven US patients with enlarged hearts.23 A review of 14 studies conducted between 1984 and 1994 showed that Co-Q10 increased the stroke volume and cardiac output of patients with congestive heart failure.24
- Vitamin B6 supports natural Co-Q10 production in living tissues, so supplementing with this B vitamin and Co-Q10 is reasonable.25 Magnesium also is an essential nutrient in the production of ATP.26
- Herbal approaches to overcome fatigue may also be beneficial, particularly because of minimal side effects. Rhodiola (Rhodiola rosea) has been reported to reduce stress-related fatigue. In a placebo-controlled, double-blind, crossover trial, low-dose treatment with a standardised extract of rhodiola reduced symptoms of fatigue in 56 young, healthy male and female physicians on night duty. Subjects in the two-week study took 170mg/day, containing approximately 4.5mg salidroside.27
In some cases, unexplained fatigue may be a physical symptom of masked depression. St. John's wort (Hypericum perforatum), 900mcg/day, was used in a small pilot study of 17 women and three men with reported depression lasting for at least two weeks. At the end of the study, only three subjects were still classified as depressed/borderline, and five as anxious/borderline.28
Fatigue often has elusive origins, but accompanying symptoms often provide clues. Nutritional factors play a primary role in fatigue resolution.
Bill Sardi is a health journalist writing from Diamond Bar, California. He is the author of The Iron Time Bomb (Bill Sardi, 1999).
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