Lake trout (Salvelinus namaycush), also known as lake char, is a fatty fish found primarily in U.S. and Canadian lakes such as the Great Lakes. Lake trout is a very good source of astaxanthin, omega-3 fats and vitamin B12, and a good source of choline, CoQ10, and vitamin B6, most of which have been linked to lower breast cancer risk.
Consumption of fatty fish or fish oil has been found to reduce the risk of coronary heart disease. Eating fatty fish 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 lake trout

Relatively high fatty fish intake has been shown to be associated with reduced risk of breast cancer. Lake trout marine carotenoid astaxanthin and omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have been shown to have chemopreventive properties.

Human studies

Many epidemiological studies have found convincing evidence of a negative association between DHA and EPA intake or fatty fish consumption and the risk of breast cancer. One study reported that DHA increased survival times for almost half of a group of stage IV breast cancer patients on FEC (5-FU, epirubicin and cyclophosphamide) chemotherapy.
In addition, several studies have found that higher dietary omega-3 to omega-6 fatty acid intakes are associated with reduced risk of breast cancer; consuming lake trout would improve this ratio for most women.

Astaxanthin

Wild caught lake trout with red, pink or orange flesh is a source of astaxanthin, a red-colored carotenoid derived from algal phytoplankton consumed by the fish. (Food coloring may be added to the feed of farmed lake trout to give it the rich color of wild lake trout.)
Astaxanthin has been demonstrated to inhibit the growth and proliferation of ER+/PR+ and ER-/PR-/HER2+ breast cancer cells in several studies. In addition, pretreatment with astaxanthin was found to increase the toxicity of Adriamycin or 5-fluorouracil (5-FU) by 40% to 50% in triple negative (ER-/PR-/HER2-) breast cancer cells in one study.
Astaxanthin has also been found to reduce the incidence of palpable mammary tumors in a mouse model of carcinogen-induced breast cancer. Furthermore, astaxanthin has been shown to reduce Adriamycin-induced heart damage in rats.
Note that synthetic astaxanthin has significantly less antioxidant properties than algal-based astaxanthin and may be be unsuitable as a supplement, according to one study.

Marine omega-3 fats

Like other fatty fish, lake trout is a significant source of the marine omega-3 fatty acids EPA and DHA. These fatty acids have been shown to inhibit proliferation of breast cancer cells in the laboratory. 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. Fish protein has been shown to have antiproliferative activity against human breast cancer cell lines.
Marine omega-3 fats and breast cancer treatment
Marine fatty acids have been found to enhance the therapeutic effects of tamoxifen and chemotherapy drugs such as Adriamycin and Taxol.

Lake trout can accumulate harmful contaminants

Generally speaking, the benefits of consuming fatty fish, including lake trout, are thought to outweigh the potentially detrimental effects of the toxins from pollution and other sources that tend to accumulate in their adipose tissue. Lake trout is not considered a high mercury fish, although relatively high levels have been recorded in lake trout from some Canadian lakes.
However, as a large predatory fish at the top of its food chain, lake trout tends to accumulate environmental contaminants present in its home waters. In fact, depending on its location, lake trout can accumulate levels of chemicals high enough to be detrimental to human health.
For example, while the situation has improved in recent years, the Great Lakes are contaminated with many pollutants, including polychlorinated biphenyls (PCBs), polychlorinated dibenzo dioxins and furans, polybrominated diphenyl ethers, and mercury, as well as chlorinated pesticides such as dichlorodiphenyltrichloroethane (DDT) and its metabolites. The U.S. Environmental Protection Agency and Environment Canada perform ongoing monitoring of whole-body contaminant levels of top predator fish such as lake trout.
Generally speaking, women can safely eat up to eight servings of lake trout per month, assuming it is not from a lake considered contaminated. However, lake trout should be avoided by pregnant women and nursing mothers due to its contaminant content. Removing the skin from lake trout is recommended to reduce the level of contaminants ingested.
Given the above, it is important for consumers to investigate the origin of any lake trout they obtain (whether wild caught or farmed) and determine its safety profile.

Additional comments

Lake trout should not be confused with rainbow trout (Oncorhynchus Mykiss), which is one of the most common farmed fish and does not have the same favorable omega-3 fatty acid profile.
Pan frying fatty fish has been shown to release carcinogenic heterocyclic amines (HCAs) in concentrations high enough to affect human health. Population studies have also found that consumption of fried fish is associated with increased risk of breast cancer.
Wild caught is more beneficial than farmed lake trout
Wild caught lake trout is a better choice than farmed lake trout. Wild lake trout normally will have a higher omega-3 to omega-6 fatty acid ratio than farmed lake trout since commercial lake trout feed is often partially plant-based. In addition, the concentrated mix of fishmeal and fish oil also used in feeds tends to be high in contaminants. As noted above, farmed lake trout has lower levels of astaxanthin than wild caught (and food coloring may be added to the feed to improve flesh color). In addition, farmed lake trout may be treated with antibiotics, pesticides and hormones to help them grow size and keep them healthy in the crowded pens in which they are raised.
Please see our article on fatty fish and the lake trout tag for more information.