Essential Fatty Acids and Stress
Authors: Rakesh Kapoor, PhD, Artur Klimaszewski, MD and Janice McColl, BSP, MSc, MH
In today’s hectic lifestyle stress and its harmful effects seem to be unavoidable. Stress is a very complex chain of events involving psychological, physiological, and environmental factors and resulting in a host of physiological and biochemical events. Some of the damaging effects on the body are postulated to be related to the deficiency of essential fatty acids (EFAs) which may occur during stress due to inhibition of enzymes involved in formation of long chain polyunsaturated fatty acids, which are essential for the normal functioning of each and every organ. This review will examine how EFAs may influence the major systems of the body that are affected by stress such as mental functions, and the gastrointestinal and cardiovascular systems. Supplementation of EFAs in the diet, such as a combination of borage oil, flaxseed oil and fish oil, may be theorized to prevent stress and indirectly, illnesses associated with stress.
Essential Fatty Acids
Essential fatty acids are polyunsaturated fatty acids that are essential for the normal functioning of the human body and must be supplied by the diet as the body can not synthesize them. They include linoleic acid (LA) and alpha linolenic acid (ALA), and their derivatives. LA is metabolized in the body to gamma linolenic acid (GLA) by the enzyme delta-6-desaturase (D-6-D). This is the slowest, rate-limiting reaction in the metabolism of LA. GLA is elongated to dihomo gamma linolenic acid (DGLA) which is acylated and incorporated in the membrane phospholipids. DGLA can also be desaturated to arachidonic acid (AA) which is then acylated and incorporated in membrane phospholipids. These EFAs impart fluidity to cell membranes, and determine the biological properties of the membranes. By imparting the characteristic three dimensional structure, they control the actions of various proteins including ion channels and hence control the permeability of cell membranes. During stimulation, phospholipase A2 releases these EFAs from the cell membranes. DGLA competes with AA for metabolic enzymes (cyclooxygenase and lipoxygenases) to produce monoenoic prostaglandins, which exhibit anti-inflammatory and anti-aggregatory activity. AA produces dienoic prostaglandins that have proinflammatory, proaggregatory and vasoconstrictor actions. In a similar fashion as LA, ALA is metabolized to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA gives rise to trienoic prostaglandins that are weakly proinflammatory. DGLA and EPA compete with AA for production of prostaglandins and hence regulate inflammatory responses. These EFAs can also act directly to regulate various cell processes through a huge number of processes such as regulation of gene expression, and modulation of neurotransmitters, hormones and cytokines. Through these many and diverse roles, EFAs impact numerous physiological reactions in the body. EFAs are perhaps best known for their cardiovascular benefits. However, they can benefit all systems in the body, including those systems that are affected by acute and chronic stress.
The most important essential fatty acids with respect to their effects on physiological processes related to stress are GLA, ALA, EPA and DHA. GLA is found in high amounts in borage seed oil, and in lesser amounts in black currant oil and evening primrose oil. ALA is found in high amounts in flaxseed oil. EPA and DHA are found in varying amounts in fish oil. Strict vegetarians who do not eat fish obtain EPA and DHA from the metabolism of ALA. During the response to stress, levels of these essential fatty acids and their eicosanoid metabolites may be reduced. This may be due to increased utilization or reduced metabolism of EFAs, such as through inhibition of the D-6-D and phospholipase A2 enzymes. Recent research suggests that supplementation with these essential fatty acids may be effective in reducing the effects of stress.
Physiology and pathophysiology of stress
Stress is a complex series of events in response to stressors and may be defined as the non-specific response of the body to any demands made upon it. The stress response is often simply referred to as the “fight or flight” response – the response that helps organisms deal with situations of stress by either standing their ground and fighting or turning tail and running away. Physiologically speaking, a multitude of events occurs with stress, irrespective of the cause. One such event is a release of hormones including catecholamines (epinephrine and norepinephrine), cortisol, and others. These are released in situations of both acute and chronic stress. Catecholamines prepare the body for the “fight or flight” response and have powerful effects on all body tissues, including sharpening of our senses, stimulation of the heart, increased blood pressure, and preparation of our cardiovascular system for increased exertion.
A moderate level of stress can be useful, such as to get our body systems working optimally in an emergency, but the human body was not designed to operate under chronic, unrelenting strain. Prolonged stress has been linked to various problems such as hypertension, heart disease, fatigue, gastrointestinal disturbances such as ulcers and irritable bowel syndrome, and problems with brain cognitive functions such as reduced learning and memory and increased violence and aggression. Chronic stress can increase our chance of getting a heart attack, hypertension, allergies, ulcers, skin rashes, insomnia and many other medical conditions.
While stress management is clearly important in reducing recurrent and chronic stress and its effects on the body, research has shown that administration of essential fatty acids may be able to attenuate several manifestations of stress and reduce the damage caused by high chronic levels of cortisol and catecholamines.
EFAs and Mental Health
Supplementation with essential fatty acids has many beneficial effects in treating mental disorders and dysfunction. Fish oil supplementation reduces hostility and stress, demonstrated in healthy students during stressful final exams. Supplementation with GLA, EPA and DHA has improved symptoms of chronic and postviral fatigue syndrome including fatigue, dizziness, poor concentration and depression. Other beneficial effects include improved mood and depression, enhanced learning and memory, and prevention of brain damage.
EFAs and Gastrointestinal System
Essential fatty acids may protect against ulcers, which commonly occur with chronic stress. Altered prostaglandin production in the gastroduodenal mucosa, due to cortisol, may be responsible, at least in part, for the development of ulcer disease. Supplementation with EFAs, such as GLA, may increase endogenous production of cytoprotective prostaglandins, and may also, themselves, possess cytoprotective properties with the ability to enhance ulcer healing, as well as provide protection against ulcers by inhibiting the growth of Helicobacter pylori.
In animals, GLA has been shown to offer protection from ulcerogenic agents such as ethanol, steroids and non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin. It is interesting to note that patients treated with H2 blockers such as famotidine, exhibit increased GLA levels. H2 blockers may enhance the healing of the duodenal ulcer by activating D6D and other enzymes, so that levels of various EFAs revert to normal. In a small human study, GLA supplementation in the form of evening primrose oil was found to completely heal duodenal ulcers within a period of four to six weeks.
EFAs and the Cardiovascular System
Studies on humans demonstrate that GLA lowers stress-related hypertension. In a 1996 study published inThe Journal of Human Hypertension, patients who received 1 gram of GLA daily for 8 weeks demonstrated up to 40% less increase in blood pressure during subsequent experimental stress tests, compared to the placebo group. An earlier study done in 1989 showed that GLA reduced the hypertensive response and improved the accuracy of those exposed to experimental stress, which suggests that GLA may lead to an enhanced ability to focus in critical moments.
Results from a large multi-center clinical trial published in 1999 evidenced lower mortality rate from cardiac causes in people taking fish oil supplements.24 This may be due to electrical stabilization of the cardiomyocytes. Likely, the same mechanisms may protect the cardiac rhythm during chronic stress.
Natural balance of dietary essential fatty acids may be the key
Our human ancestors were scavengers who lived on a diet quite high in essential fatty acids.26 Genetically, we still have similar dietary requirements. Today’s diet, with its high levels of saturated and trans fatty acids, is also low in EFAs. Hence, supplementation of EFAs has strong merits. Today, many people take fish oil as a protection against heart diseases, others take borage oil to relieve their arthritic pain or help their eczema, and still others take essential fatty acids for the maintenance of good health or as a form of disease prevention “in general.” Much like a multivitamin, a “multi-EFA” that contains a balanced blend of borage, flaxseed and fish oils, is becoming increasingly popular, especially for maintenance of good health. Regular supplementation for several weeks is usually necessary to achieve noticeable results. Research is beginning to suggest that this type of supplement may potentially be useful in the prevention or management of stress.
Hundreds of clinical trials on EFAs confirm safety with no reports of any serious side effects. Only diarrhea and abdominal bloating seem to be, on occasion, a problem. However, these benign side effects are easy to control with dosage reduction, or by taking the daily dosage in divided portions. Caution should be observed when supplementing with high doses of fish oils in patients taking anti-coagulants since bleeding times may be prolonged.
Research to date has demonstrated that essential fatty acids have important effects on many body systems. Early research suggests that essential fatty acids may be helpful in reducing the development of stress and the resulting harmful effects on the body. Although research to date is encouraging, more research is needed to clarify the role of essential fatty acid supplementation in the management of stress.