Like herring, mackerel is a good source of choline, coenzyme Q10 (CoQ10), selenium, vitamin B12, vitamin D and omega-3 polyunsaturated fatty acids. Generally speaking, the benefits of consuming fatty fish are thought to outweigh the potentially detrimental effects of the toxins from pollution and other sources that tend to accumulate in their adipose tissue. Consumption of fatty fish or fish oil has been found to reduce the risk of coronary heart disease. Consumption of dried mackerel was shown in one study to improve the learning ability of laboratory mice, apparently by increasing the level of the marine omega-3 fatty acid docosahexaenoic acid (DHA) in their brains. Eating fatty fish such as mackerel has been found to be associated with reduced risks of leukemia, multiple myeloma, and non-Hodgkin lymphoma, as well as renal cell, endometrial and prostate cancer.
Breast cancer-related effects of eating mackerel
Like other fatty fish, mackerel contains the marine fatty acids DHA and eicosapentaenoic acid (EPA), which have chemopreventive properties. These marine fatty acids have been shown to inhibit proliferation of breast cancer cells in the laboratory. Relatively high fatty fish intake has been shown to be associated with reduced risk of breast cancer and improved survival. In one experiment, higher omega-3 to omega-6 fatty acid diets reduced mammary gland density in mice, which in turn reduced carcinogen-induced mammary tumor development. Fish oil has been shown to inhibit early stages of mammary tumor development in a mouse model of HER-2/neu overexpressing (HER2+) breast cancer. DHA has been demonstrated to reduce bone metastasis in a mouse model of breast cancer.
Many epidemiological studies have found convincing evidence of a negative association between DHA and EPS intake or fatty fish consumption and the risk of breast cancer, although not all are in agreement. One study concluded that higher intakes of fish were actually associated with higher incidence rates of ER+ breast cancer for postmenopausal women. Several studies have found that higher omega-3 to omega-6 fatty acid ratios are associated with reduced risk of breast cancer; consuming mackerel would tend to improve the ratio for most women.
Marine fatty acids have also been found to enhance the therapeutic effects of tamoxifen and chemotherapy drugs such as Adriamycin and Taxol. However, note that recent research suggests that mackerel and similar fish should not be consumed the day before through the day after a chemotherapy treatment and in moderation during the remaining days of each cycle. Mackerel contains a fatty acid (hexadeca-4,7,10,13-tetraenoic acid) that can induce resistance to a broad spectrum of chemotherapy drugs.
Mackerel consumption should be reduced or eliminated by pregnant and nursing mothers since toxins from pollution and other sources might reduce birth weight and are secreted in breast milk. While mackerel is not generally considered a high mercury level fish, king mackerel and other mackerel from the Gulf of Mexico have been found to have high levels of mercury and other heavy metals and should be avoided.
We recommend against consuming all but modest amounts of smoked mackerel, dried mackerel, salted dried mackerel, or mackerel pâté since such preserved fish foods have been associated with increased risks of gastric, colorectal and other cancers.
Pan frying mackerel has been shown to release carcinogenic heterocyclic amines (HCAs) in concentrations high enough to affect human health. Population studies have found that consumption of fried fish is associated with increased risk of breast cancer.
Below are links to recent studies concerning this food. For a more complete list of studies, please click on mackerel.