Dairy milk fat augments paclitaxel therapy to suppress tumour metastasis in mice, and protects against the side-effects of chemotherapy

Milk fat is a natural product containing essential nutrients as well as fatty acids and other food factors with reported anti-cancer potential. Here bovine milk fat was tested for its ability to inhibit the growth of breast and colon cancers and their metastasis to the lung and liver; either alone or in combination with the chemotherapeutic agent paclitaxel. A diet containing 5% typical anhydrous milk fat (representing ~70% of the total dietary fat component) fed to Balb/c mice delayed the appearance of subcutaneous 4T1 breast and CT26 colon cancer tumours and inhibited their metastasis to the lung and liver, when compared to the control diet containing soybean oil as the only fat component. It augmented the inhibitory effects of paclitaxel on tumour growth and metastasis, and reduced the microvessel density of tumours. It displayed no apparent organ toxicity, but instead was beneficial for well-being of tumour-bearing mice by maintaining gastrocnemius muscle and epididymal adipose tissue that were otherwise depleted by cachexia. The milk fat diet ameliorated gut damage caused by paclitaxel in non-tumour-bearing mice, as evidenced by retention of jejunal morphology, villi length and intestinal γ-glutamyl transpeptidase activity, and inhibition of crypt apoptosis. It prevented loss of red and white blood cells due to both cancer-mediated immunosuppression and the cytotoxic effects of chemotherapy. The present study warrants the use of milk fat as an adjuvant to inhibit tumour metastasis during cancer chemotherapy, and to spare patients from the debilitating side-effects of cytotoxic drugs.