New study warns breast cancer patients should avoid fatty foods

By Stephen Beech

Breast cancer patients should avoid fatty foods, warns a new study.

Researchers found that a high-fat diet accelerates the growth and spread of breast cancer tumors.

The effects of high-fat diet are more impactful than glucose, insulin, and ketone levels in triple-negative breast cancer, according to the findings published in the journal APL Bioengineering.

A multidisciplinary team of researchers at Princeton University set out to discover what patients diagnosed with breast cancer should eat to ensure the best prognosis.

Study author Professor Celeste Nelson said: “We took the approach of building identical engineered tumors and culturing them in conditions that mimic the blood composition of patients under different dietary states.

“We were hoping to identify dietary conditions that would slow tumor growth.

"Instead, we found one dietary condition - a high-fat diet - that sped up tumor growth.”

The research team engineered a tumor model using a human plasma-like medium to re-create a more realistic microenvironment around tumors.

That allowed them to replicate the biochemical effects of nutrients from food.

As a result, they could isolate specific nutrients and their effects and closely examine the metabolic reprogramming that occurs in cancer cells.

The study focused on triple-negative breast cancer, a subtype that is particularly difficult to treat with standard methods.

The research team examined the structure, growth, and spread of cancer cells and how the characteristics differ in four different dietary conditions that can occur in a human body: high-insulin, high-glucose, high-ketone, and high-fat.

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They discovered a high-fat diet accelerates tumor growth and invasion.

The team also found it causes an increase in the enzyme MMP1, which degrades the extracellular matrix, and is associated with a poor prognosis.

Using their results, the researchers say they will be able to apply their method to other breast cancer subtypes and scenarios.

Previous studies to examine the connection between diet and tumor growth failed to account for the complexity of interconnected systems in the body.

Nelson explained that the interplay between the immune system, human tissues involved in metabolism, and the microbiome of trillions of microorganisms in the body affects how cancer cells behave.

She said cells in the body are bathed in a water-based fluid, called interstitial fluid, that flows continuously around them.

Earlier studies examining how nutrients from food affect tumors have struggled to replicate the constant flow of nutrients around cells.

Nelson said: “Cells are typically cultured in media that is saturated with sugars and other biochemicals at levels that don’t match what you see in the human body.

“Our study shows that tumor cells behave differently when cultured in media that matches the biochemical composition of human plasma.”

The research team plan to use their results to further examine the link between diet and various tumor therapies.

Nelson added: “We plan to take the same system and define whether tumors respond differently to chemotherapy when cultured in media mimicking the different dietary conditions.

“This would allow physicians to potentially make recommendations about what a patient should eat if prescribed a specific therapy.”