Fish has been an important source of protein for many people around the world. It not only gives us fish oils but is super source of minerals like selenium but also iodine, vitamin D, vitamin E, vitamin B12 and of course long-chain omega-3 polyunsaturated fatty acids (PUFAs) (n-3 PUFAs) (Weichselbaum et al., 2013). Fish consumption must be one of the best examples we can improve upon if we are to enjoy its many benefits.
Fish consumption is recommended by the American Heart Association as well as by other nutrition bodies (Van Horn et al., 2016). It’s also regularly considered in advice on dietary guidelines. Fish itself has regularly been regarded as part of the Mediterranean and Nordic diets (Trichopoulou et al., 2003; Calton et al., 2014).
The Japanese are no slouches either as they probably consume the most seafood of any nation. They regularly consume salmon, amberjack, tuna of various types and a fish called pacific saury.
Fish consumption might lower our risk of heart attack and associated strokes.
Strokes and heart attacks are one of the most common causes of early death in adult populations. There are plenty of observational studies that have demonstrated eating fish lowers the risk of us suffering from heart attacks, strokes and from various forms of heart disease (Djousse et al., 2012).
One extremely large study involving 40,000 mean in the United States of America has shown that eating one or more servings of fish produced a 15% lower risk of heart disease (Virtanen et al., 2008).
Generally speaking, the fatty types of fish are probably best of all for their heart health benefits because they are particularly rich in omega-3 fatty acid.
Fish consumption may have considerable benefits in reducing risk of breast cancer.
A recent study conducted by Zhejiang University, Hangzhou in China has reported that increased consumption of dietary marine n-3 PUFAs (polyunsaturated fatty acids) might reduce the risk of breast cancer. These findings were based on examination of 26 publications reporting the incidence of breast cancer versus dietary intakes of both fish and n-3 PUFA which were conducted in prospective cohort studies (Zheng et al., 2013).
Breast cancer still remains one of the leading cancers in women making up 23% of the total and 14% of all cancer deaths in 2008 (Jemal et al., 2011). Indeed, over 800,000 women including 20,000 who had breast cancer from a number of continents were part of the examination. Dietary fat is one of the prominent risk factors in the appearance of this cancer. The risk was lowest in Asian populations because it is reasoned more fish is eaten.
The PUFAs are essential nutrients because they are not synthesised by the body and must be consumed. Fish is the main source although nuts and seeds provide one of the components such as ALA (alpha-linolenic acid). Consumption of fish PUFAs was associated with a 14% reduction in breast cancer based on figures for the highest and lowest category of PUFA intake. The researchers felt that in terms of diet, the marine PUFAs offered a protective effect and requires further study.
Fish Consumption May Help Reduce Other Forms Of Cancer Risk
Varying effects have been noted on various types of cancer where fish consumption is concerned (Kim & Mason, 1996). There are a number of other reports to add in this sense and we will discuss them as they come in.
One recent particular study conducted by the University of Oxford with the International Agency for Research on Cancer (IARC) looked at the dietary habits of 476,160 people. They relied on questionnaires about how often they ate particular food types. One aspect looked at fish intake and the types of fish eaten including oily, fatty or lean fish, white and brown. One strong finding was an association with a reduction in bowel cancer and increasing levels of fish eating.
Raising Fish Consumption Might Reduce Risk Of Dementia.
The Japanese are renowned for eating fish. One study in the British Journal of Medicine suggests that dementia in healthy and elderly Japanese people may be lowered in this population because they consumer so much fish (Tsurumaki et al., 2019).
in the past, a few studies looked at this association between fish eating and a number of mental disorders but in over half of them, the reported benefits were not statistically significant and that association could not be clearly made.
In this study the association appears to be shown much more clearly. The researchers examined 13,000 individuals of 65 years old or above with no disabilities. Participants came from the Ohsaki Cohort 2006 group living in Ohsaki City in Japan. They were followed for nearly 6 years. Information was collected using food frequency questionnaires and covered their levels of fish consumption as well as other foods at baseline. The fish covered all forms consumed – raw, grilled, boiled and so on. It also included fish paste too.
The level of fish consumption was divided into four quartiles based on amount i.e. Q1 (lowest level), Q2, 3 & 4 (highest amount). People in the Q1 quartile were the reference category.
Onset of dementia was the main measure of the outcome of this study. This was defined as to whether it was disabling or an incident functional disability based on criteria used by the Japanese in their LTCI system.
The LTCI system is a dementia scale classified into six ranks from 0, I to IV, and M. It might seem complicated but has served a means of classifying dementia in Japanese medical circles. The 0 rank means no dementia incident of any sort. The rank M means a severe dementia-related behavioural disturbance that needs medication of some sort. Any rank exceeding I is an outcome measure of incident dementia. Rank II refers to a mild or moderate form of dementia.
The main findings showed that compared to Q1 who were people consuming the least fish, the hazard ratio for incident dementia was 0.77 for Q2, 0.74 for Q3 and 0.70 for Q4 based on a probabality statistic of p<0.01.
The conclusion was an inverse association between fish consumption and the onset of dementia. It suggested that fish intake was beneficial for preventing dementia.
The reasons they thought responsible was the high level of omega-3 fatty acids such as docoahexanoic acid (DHA) and eicosapentaenoic acid (EPA) in their diet. This ties in with other studies on fish oil consumption which are known to potentially reduce a decline in cognition.
Fish also contain plenty of other nutrients such as vitamin A, D, B12 and E as well as selenium which have neuroprotective benefits.
The study is not without its issues which they acknowledge. Collecting fish consumption using questionnaires always has caveats especially when collected at baseline. All the participants may have altered their intake of fish over the time period and during follow-up. The study length was also relatively short even though the future longevity of the age group was similarly shorter than with others. A longer follow-up period would have been statistically more beneficial to the study.
Fish As A Secure Source Of Vitamin D
Vitamin D is a very important vitamin where it behaves in a manner similar to steroidal hormones. It is estimated that nearly 42% if people in the USA are either deficient if not low on this vitamin (Forrest & Stuhldreher, 2011).
Fish and other products made from fish are one of the top sources of vitamin D with the fatty fish like salmon and herring containing some of the highest amounts.
References
Calton, E.K., James, A.P., Pannu, P.K., Soares, M.J. (2014) Certain dietary patterns are beneficial for the metabolic syndrome: reviewing the evidence. Nutr. Res. 34(7) pp. 559–68 (Article)
Djoussé, L., Akinkuolie, A. O., Wu, J. H., Ding, E. L., & Gaziano, J. M. (2012). Fish consumption, omega-3 fatty acids and risk of heart failure: a meta-analysis. Clinical nutrition (Edinburgh, Scotland), 31(6), pp. 846–853 (Article).
Forrest, K.Y.Z., Stuhldreher, W.L. (2011) Prevalence and correlates of vitamin D deficiency in US adults. 31(1) pp. 48-54 (Article) .
Jemal, A., Bray, F., Center, M.M., Ferlay, J., Ward, E., Forman, D. (2011) Global cancer statistics. CA Cancer J. Clin. 61pp. 69-90
Trichopoulou A, Costacou T, Bamia C, Trichopoulos D. (2003) Adherence to a Mediterranean diet and survival in a Greek population. N. Engl. J. Med. 348(26) pp. 2599–608 (Article)
Tsurumaki, N., Zhang, S., Tomata, Y., Abe, S. (2019) Fish consuption and risk of incident dementia in elderly Japanese: the Ohsaki cohort 2006 study. British J. Nutr. 11(10) pp. 1182-1192 (Article)
Van Horn L, Carson JA, Appel LJ, Burke LE, Economos C, Karmally W, Lancaster K, Lichtenstein AH, Johnson RK, Thomas RJ et al. (2016) Recommended dietary pattern to achieve adherence to the American Heart Association/American College of Cardiology (AHA/ACC) guidelines: a scientific statement from the American Heart Association. Circulation. 134(22):e505–e29 (Article).
Virtanen, J.K., Mozaffarian, D., Chiuve, S.E., Rimm, E.B. (2008) Fish consumption and risk of major chronic disease in men. Am J Clin Nutr. 88(6) pp. 1618–1625. (Article)
Weichselbaum, E., Coe, S., Buttriss, J., Stanner, S., (2013) Fish in the diet: a review. Nutr Bull. 38 pp. 128-77 (Article)
Zheng, J.-S., Hu, X.-J., Zhao, Y-M., Yang, J. Li, D. (2013) Intake of fish and marine n-3 polyunsaturated fatty acids and risk of breast cancer: meta-analysis of data from 21 independent prospective cohort studies. BMJ 2013; 346: f3706 (Article) doi: (Published 27 June 2013)
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