The following appeared as part of an article in a health magazine.

“A new discovery warrants a drastic change in the diets of people living in the United States. Two scientists have recently suggested that omega-3 fatty acids (found in some fish and fish oils) play a key role in mental health. Our ancestors, who ate less saturated fat and more polyunsaturated fat, including omega-3 fatty acids, were much less likely to suffer from depression than we are today. Moreover, modern societies – such as those in Japan and Taiwan – that consume large quantities of fish report depression rates lower than that in the United States. Given this link between omega-3 fatty acids and depression, it is important for all people in the United States to increase their consumption of fish in order to prevent depression.”

The given argument draws the conclusion that the residents of the United States should increase their consumption of fish to avoid depression. This assertion has been supported by stating that omega-3 fatty acids are related to depression. The arguer presents some facts to reinforce this statement. The first fact is the suggestion given by 2 scientists that omega-3 fatty acids play a key role in mental health. These acids are found in some fish and fish oils. The second fact is that our ancestors who had a diet rich in omega-3 fatty acids were less likely to suffer from depression as compared to the present generation. The third fact is that the depression rates among fish-consuming people like those living in Japan and Taiwan is quite low. According to the arguer, these 3 facts prove beyond doubt that omega-3 fatty acids and depression are related. Therefore, increasing the intake of omega-3 fatty acids is bound to prevent depression. However, there are numerous loopholes in the argument that fail to convince the reader that omega-3 acids and depression are related.

The first loophole in the argument is that just because omega-3 fatty acids play a key role in mental health does not mean that they are related to depression and that they are necessary for good mental health. They may be related to some form of mental health other than depression. Additionally, this suggestion has been made by just two scientists and utilizing this suggestion as a base for drawing the conclusion that a higher intake of omega-3 fatty acids is necessary to fight depression does not sound well-reasoned at all.

The second fact does nothing to support the given conclusion as it is a well known fact that the lifestyle of our ancestors was much different from that of the present generation. There may have been a variety of other reasons that were responsible for low rates of depression among them. The present generation leads a fast paced life which is the root cause for a number of mental stress related disorders like depression. Therefore, it is quite likely that the intake of fish had nothing to do with the likelihood of our ancestors being depressed.

The third fact is the weakest link in the given argument. One cannot draw parallels between the residents of the United States and those of Japan and Taiwan. Depression rates may differ among the citizens of different countries due to varied reasons like different lifestyles, working conditions and climatic conditions. Nowhere in the argument has the arguer referred to the type of fish that these fish-consuming people are including in their diet. It has been mentioned in the argument that omega-3 fatty acids are present in some fish and fish-oils. It is not necessary that all types of fish will be rich in omega-3 fatty acids.

The argument could have been well reasoned if the arguer had provided more evidence that proved beyond doubt that omega-3 fatty acids are related to depression and that the types of fish that are being consumed by the people of Japan and Taiwan are the ones that contain omega-3 fatty acids. Therefore, lack of strong evidence has rendered the given argument weak and made the conclusion sound unconvincing.