Decosahexaenoic Acid (DHA)

As an increasing number of research findings have been linking diets rich in fat content to diseases like cancer and heart attacks during the last one decade or so, more and more people have become conscious about what they consume and cautiously counting their daily fat intake. However, in their over-enthusiasm over eliminating fats from their diets, it is likely that many people have even shunned some good fats, such as decosahexaenoic acid or DHA. In fact, though DHA is a crucial fatty acid for the body, it is not produced by our body.

Interestingly enough, many people have shunned DHA, which is present in foods, believing that it is detrimental for good health. Foods like organ meats that contain rich amounts of both - saturated fat and toxins as well as eggs that are likely to contain very high amounts of cholesterol for individuals enduring lipid problems. DHA is also present in abundance in fatty fish, such as salmon, sardines, mackerel and albacore tuna. It is also found in high intensity in the gray matter of the brain as well as the retina of the eye. In addition, DHA is also active in the functioning of the brain cell membranes that are responsible for the communication of signals from the brain. Hence, the moot question remains as to what is DHA and why it is essential for the body.

In effect, decosahexaenoic acid or DHA is an omega-3 fatty acid, named so as it has double-bond 3 carbon atoms ahead of the methyl end of the long carbon-series carboxylic acid. It may be mentioned that among all the fatty acids that are indispensable in the human diet include only omega-3 or omega-6. While it is possible to synthesize decosahexaenoic acid (DHA) in the body from alpha-linolenic acid - an uncomplicated omega-3 present in linseed oil and perilla oil, the ability for amalgamation reduces with advancing age. Hence, as one grows older, he or she is able to obtain more advantages by ingesting dietary supplements containing DHA. The omega-3 and omega-6 family of fatty acids are indispensable since neither can be created in the body and has to be taken from our diet. While fatty acids are found in the membranes of all cells in our body, the essential fatty acids are especially concentrated in the brain cell, heart cell and immune-system cell membranes.

Decosahexaenoic acid or DHA has be found to be indispensible for the usual development of the brain and eyes and is transmitted from the mother to the fetus by means of the placenta. Following the birth of the infant, breast milk forms the major source of this essential item. It may be noted here that the scientists are presently worried that the consumption of DHA has declined considerably as well as rapidly over the last five decades or so. It has been found that in countries where the consumption of DHA has remained high, there are fewer cases of depression or mood changes among the people. In fact, people who have poor intensity of decosahexaenoic acid or DHA have been found to suffer from conditions, such as dementia (deterioration of intellectual faculties), mood swings, and loss of memory as well as vision problems. A research conducted by Swedish scientists on elderly patients suffering from Alzheimer's disease found that they had poor levels of DHA in their bloodstream in comparison to other elderly people who possessed sound health. In addition, a research undertaken by Japanese scientists on the subject demonstrated that when patients enduring dementia were provided with DHA supplements, they showed as high as 65 per cent improvement in their condition.

Another aspect that is worrying the scientists is the fact that they have found breast milk having much reduced levels of decosahexaenoic acid (DHA) presently. They are apprehensive that this may eventually hinder the usual development of the children's brains. Hence, DHA is especially added to dietary formulas for children in Europe. Moreover, the scientists are of the view that insufficiency of decosahexaenoic acid or DHA is largely responsible for the increasing incidents of postpartum depression in women who have just given birth.

Alzheimer's disease

An intervention trial is being carried out by the US National Institute of Health (NIH) on a large scare with a view to appraise the utility of DHA in combating as well as preventing various diseases. In fact, the experimentation undertaken by the NIH is the first ever trial of decosahexaenoic acid (DHA) and Alzheimer's disease that is being conducted on such a grand scale.

Earlier, the US National Institute on Aging (NIA) had conducted an 18-month long study with people suffering from mild to moderate Alzheimer's disease. This study - called Alzheimer's Disease Cooperative Study (ADCS), was led by an Associate Professor of Neurology at the Oregon Health and Sciences University Joseph Quinn, MD, and supported by the scientists from the National Institute on Aging. The team of scientists led by Dr. Quinn conducted a double blind, riffled and placebo-regulated clinical experimentation measuring up DHA and placebo in as many as 402 people having an average of 72 years and found to be suffering from mild to moderate Alzheimer's disease. This study was conducted at 51 locations all over the United States. During the course of their research, scientists found that when these Alzheimer's patients were treated with DHA there was a significant rise in the intensity of decosahexaenoic acid in their bloodstream. Most importantly, on the basis of the measured enhancement of DHA in the cerebrospinal fluid of the people who participated in the study, the scientists found that treatment with DHA resulted in an augmentation of decosahexaenoic acid levels in the brain.

Nevertheless, treatment with DHA did not inhibit the pace of alteration on examinations of the cerebral performance (ADAS-cog), activities of daily living (ADL), global dementia severity level (CDR-SOB) or the interactive or behavioural symptoms (NPI) on the subjects who participated in the experimentations in general. In addition, no difference was also observed in the DHA treatment of the patients suffering mild or moderate intensity of Alzheimer's disease.

Joseph Quinn later stated that the results of these experiments did not endorse the idea of regularly using DHA for patients enduring Alzheimer's disease. However, studies conducted on animals in the TG3 transgenic mouse prototype of Alzheimer's disease associated a reduction in amyloid plaques as well as tau to DHA treatment in the form of taking dietary supplements. In addition, the studies conducted on animals also demonstrated that when DHA was used in combination with arachidonic acid, which is also found in fish oil, the efficacy of decosahexaenoic acid was more compared to it being used without the arachidonic acid.


According to the findings of a number of researches, compared to any other omega-3 polyunsaturated fatty acids or PUFAs, decosahexaenoic acid or DHA is also effective in inhibiting the development of malignant and invasive epithelial tumour cells in the colon of humans. In fact, it was found that the cytotoxic impact of DHA was not owing to the augmentation in lipid peroxidation or any additional damage owing to oxidation, but basically owing to a decline in the regulators that maintain cell growth. Nevertheless, the fact remains that dissimilar cancer lines tackle the polyunsaturated fatty acids (PUFAs) in separate manners and demonstrate dissimilar responsiveness to them. Such initial findings of different studies actually indicate only one thing - the need for more and detailed researches on the subject. In addition, these findings also demonstrate that there is no evidence of DHA's effectiveness or ineffectiveness in any treatment, remedy or alleviation of cancer. Nevertheless, a findings of a research undertaken in 2008 demonstrated that DHA aids in boosting the efficiency of chemotherapy in the prostate cancer cells, while another study conducted on animals in 2009 provided details of chemo-protective impact of DHA in a mouse prototype.

Pregnancy and lactation

The intensity of DHA in breast milk varies between 0.07 per cent and a little over 1.0 per cent of the entire fatty acid content, having an average of approximately 0.34 per cent. The concentration of DHA in breast milk is said to be more provided the mother's diet contains plenty of fish preparations.

Since the findings of a number of researches conducted on DHA have demonstrated that it is effective for enhancing the vision sharpness and concentration, presently use of this substance as dietary supplements has come into the notice of as well as become popular among pregnant women. A recently conducted research has suggested that poor intensity of plasma as well as erythrocyte DHA were related to a weak development of the retina, poor visual sharpness as well as improper development of the cerebral cells. This research also suggested that linolenic acid was a major DHA supply for the fetus, but, at the same time, mentioned that DHA formed beforehand or preformed DHA was more easily approved. In addition, an International Society for the Study of Fatty Acids and Lipids (ISSFAL) working group has advocated taking 300mg of DHA every day for pregnant women and nursing mothers. Contrary to this recommendation, the study has found that the mean intake of DHA supplements by women in these two groups was very low, ranging between 45 mg and 115 mg every day. Ever since 2001, numerous brands of top formulas, containing DHA as a major element for infants have been sold in North America. The trend started following the approval of the Food and Drug Administration (FDA) as well as Health Canada.

Compared to the traditional infant formula enclosing alpha-linolenic acid and linoleic acid, infant dietary supplements containing DHA are more akin to the breast milk. In fact, infant formulas containing alpha-linolenic acid and linoleic acid are forerunners of the DHA infant formulas. Presently, infant formulas marketed in North America incorporate lipids obtained from microorganisms specially cultured and developed in bioreactors as resources of decosahexaenoic acid or DHA. It is important to mention here that as of now there are no logical evaluation researches demonstrating that adding DHA to dietary supplements boosts the development of brain vis-�-vis the infants. This claim by the manufacturers of the infant formulas containing DHA in their sales promotions has prompted a number of public interest groups to lodge objections with the Federal Trade Commission of the United States. These public interest groups have alleged that the sales promotions or advertisements by the infant formula manufacturers containing DHA are not only baseless, but deceptive too.