From the Archives
Chronic fatigue syndrome (CFS) affects thousands of individuals in the US. CFS is characterized by an unexplained fatigue that does not improve with rest and lasts more than 4 to 6 months.1
Other symptoms of CFS may include headaches, unrefreshing sleep, pain, sore throat, and concentration or memory problems. It is a difficult condition to diagnose and treat. Typical causes of fatigue, such as anemia, thyroid disease, sleep apnea, adrenal dysfunction, depression, stress, and insomnia, are ruled out early on, often leaving patients with no explanation for why they are tired. Many suffer for years before finding help. The delay in diagnosis is often linked to physicians' reluctance to believe that CFS is a real condition. The current medical model in the US holds that symptoms are caused by underlying disease that can be measured by a definitive diagnostic test. CFS doesn't always fall within this model.
The cause of CFS remains unknown, perhaps because there isn't one single factor linked to CFS but instead several factors, of which many are correlative and not causative. This is what makes CFS so difficult to diagnose. Recent research has linked mycotoxins, Epstein-Barr virus, sleep abnormalities, and herpesvirus-6 to CFS.2–5 Since many physicians believe that the condition is psychosomatic, research has even been done to determine personality traits associated with CFS. A study on twins showed an association of emotional instability and extroversion with CFS.6
Alternative medicine has long considered the role of environmental chemicals in CFS. Exposure to solvents, formaldehyde, heavy metals, and pesticides has been linked to chronic fatigue.7,8 A recent study looked at a case of a CFS linked to methylmercury from fish intake. This patient ate slices of raw tuna more than twice per week for 5 years. He complained of fatigue for the past year. After an extensive workup leading to no known cause for the fatigue, mercury testing was performed. Blood and urine tests were normal, but hair mercury was elevated. After the patient took dietary supplements, aimed at reducing mercury, his hair level returned to normal and fatigue improved.9 The dietary supplement capsule contained zinc oxide, magnesium oxide, calcium, and L-cysteine. If mercury from fish can be linked to chronic fatigue syndrome, what about other chemicals in food?
Chemicals in Food
As previously stated, solvents, heavy metals, formaldehyde, and pesticides are linked to chronic fatigue syndrome. One major source of exposure to these chemicals is our diet. Not only are pesticides present as residue on fruit and vegetables, they are also in peanut butter, beef, butter, bread, ice cream, olive oil, and eggs. This has to do with the agricultural use of pesticides, which is a broad term for herbicides, insecticides, and fungicides. These are also used in and around homes. Pesticides can persist for years in the soil, contaminate groundwater and drinking water, and accumulate up the food chain.10
We are exposed to mercury, polychlorinated biphenyls (PCBs), and dioxins by eating fish. Other heavy metals such as arsenic, cadmium, and lead are also in our food. Heavy metals can be found in grains, flour, pasta, and vegetables due to contaminated soil and fertilizer. In the US, sewage sludge is commonly used as fertilizer and is contaminated with heavy metals. Fungicides containing mercury and runoff from industry-polluted waters are other sources of heavy metal contamination. The amount of heavy metals in vegetables depends on the soil conditions and fertilizer. Cadmium is the most common contaminant. The US does not limit the amount of cadmium and lead that can be present in fertilizer. The toxicants phthalates and bisphenol A leach into food stored in plastic, cooked in plastic, handled with plastic gloves, and covered with plastic cling wrap. Most food cans in the US are lined with BPA.10
Additional chemicals found in food are linked to fatigue. Many of these are food additives or naturally occurring plant chemicals. The most studied natural chemicals known to cause adverse reactions are salicylates, biogenic amines, and glutamate.
The most common biogenic amines found in foods are histamine, tyramine, cadaverine, 2-phenylethylamine, spermine, spermidine, putrescine, tryptamine, and agmatine. Biogenic amines are present in chocolate, cheese, fish products, aged or processed meats, bananas, oranges, avocados, tomatoes, wines, and beer, among other foods.11
Free (i.e., non-protein-bound) glutamate is present naturally in many strongly flavored foods such as tomatoes, mushrooms, tasty cheeses, gravies, sauces, stock cubes, meat extracts, and yeast extracts; its purified sodium salt (MSG) is also used as a flavor enhancer.
There is a clear link between food additives/chemicals such as MSG, amines, and salicylates and CFS. Liblay and Swain published their work on food intolerance and CFS as a chapter in the book The Clinical and Scientific Basis of Myalgic Encephalomyelitis: Chronic Fatigue Syndrome (1992). Preservatives, nitrates, brewer's yeast, and tartrazine are also linked. Often it is difficult to differentiate between a true allergy and an intolerance to these additives. Food allergies can cause fatigue. A recent study of 38 patients with unexplained food intolerance and food hypersensitivity reported having symptoms of chronic fatigue compared with healthy controls.12 It is proposed that they are associated through disruption of the neurological and immune systems. It could be the action of the food additive or toxicant such as pesticides and heavy metals, or these may simply be an antibody response to food.
Testing and Treatment
Given the fact that there is no singular cause for CFS, many are not sure where to begin with diagnostic tests. After ruling out causes of general fatigue and determining that the patient has chronic fatigue, testing for EBV, HHV6, mycotoxins, and sleep disturbances is a good starting point. Blood and urine testing for heavy metals, pesticides, solvents, and other chemicals are essential to finding the root cause. If toxicants are present in the body, detoxification methods to remove chemicals should be implemented. Food allergies and sensitivities need to be determined through both IgE and IgG antibody tests. Also, tests for reactions to food additives are available through several labs.
Fatigue is common in the general population. It is often described as an unusual or extreme sensation of tiredness that is not easily overcome, either by rest or by sleep. It becomes chronic when it lasts for more than 4 to 6 months. CFS affects thousands of people in the US. There is no know singular cause, yet several triggers or factors have been identified. Chemicals and additives in food are an often overlooked link to CFS. A simple food allergy test, tests for reactions to food additives, and body burden testing for chemicals can help identify this link. Avoidance of food triggers and environmental toxicants in food and detoxification may help improve the symptoms of CFS.
1. National Institute for Health and Care Excellence. Chronic fatigue syndrome/myalgic encephalomyelitis (or encephalopathy): Diagnosis and management of CFS/ME in adults and children. 7. 2007; NICE clinical guideline 53.
2. Brewer JH et al. Detection of mycotoxins in patients with chronic fatigue syndrome. Toxins (Basel). 2013 Apr 11;5(4):605–617.
3. Loebel M et al. Deficient EBV-specific B- and T-cell response in patients with chronic fatigue syndrome. PLoS One. 2014 Jan 15;9(1):e85387.
4. Jackson ML, Bruck D. Sleep abnormalities in chronic fatigue syndrome/myalgic encephalomyelitis: a review. J Clin Sleep Med. 2012 Dec 15;8(6):719–728.
5. Oakes B et al. Human endogenous retrovirus-K18 superantigen expression and human herpesvirus-6 and human herpesvirus-7 viral loads in chronic fatigue patients. Clin Infect Dis. 2013 May;56(10):1394–1400.
6. Poeschla B et al. Chronic fatigue and personality: a twin study of causal pathways and shared liabilities. Ann Behav Med. 2013 Jun;45(3):289–298.
7. Bell IR et al. Illness from low levels of environmental chemicals: relevance to chronic fatigue syndrome and fibromyalgia. Am J Med. 1998;105(3A):74S–82S.
8. Dunstan H et al. Bioaccumulated chlorinated hydrocarbons and red/white blood cell parameters. Biochem Mol Med. 1996;58:77–84.
9. Shin SR, Han AL. Improved chronic fatigue symptoms after removal of mercury in patient with increased mercury concentration in hair toxic mineral assay: a case. Korean J Fam Med. 2012 Sep;33(5):320–325.
10. Marchese M. 8 Weeks to Women's Wellness. Petaluma, CA: Smart Publications; 2011.
11. Naila A et al. Control of biogenic amines in food. Existing and emerging approaches. J Food Sci. Sep 2010;75(7):R139–R150.
12. Lind R et al. Chronic fatigue in patients with unexplained self-reported food hypersensitivity and irritable bowel syndrome: validation of a Norwegian translation of the Fatigue Impact Scale Clin Exp Gastroenterol. 2013;6:101–107.
Foods That Contain Salicylates
- Fruits such as apples, avocados, blueberries, dates, kiwi fruit, peaches, raspberries, figs, grapes, plums, strawberries, cherries, grapefruit, and prunes
- Vegetables such as alfalfa, cauliflower, cucumbers, mushrooms, radishes, broad beans, eggplant, spinach, zucchini, broccoli, and hot peppers
- Some cheeses
- Herbs, spices, and condiments such as dry spices and powders, tomato pastes and sauces, vinegar, soy sauce, jams, and jellies
- Beverages such as coffee, wine, beer, orange juice, apple cider, regular and herbal tea, rum, and sherry
- Nuts such as pine nuts, peanuts, pistachios, and almonds
- Some candies, such as peppermints, licorice, and mint-flavored gum and breath mints
- Ice cream, gelatin