Penn Study Shows an Ancient Crop Effective in Protecting Against a 21st Century Hazard

August 9, 2011
by Jessica Mikulski

Flax has been part of human history for well over 30,000 years, used for weaving cloth, feeding people and animals, and even making paint. Now, researchers from the Perelman School of Medicine at the University of Pennsylvania have discovered that it might have a new use for the 21st century: protecting healthy tissues and organs from the harmful effects of radiation. In a study just published in BMC Cancer, researchers found that a diet of flaxseed given to mice not only protects lung tissues before exposure to radiation, but can also significantly reduce damage after exposure occurs.

"There are only a handful of potential mitigators of radiation effect, and none of them is nearly ready for the clinic," says the principal investigator Melpo Christofidou-Solomidou, PhD, research associate professor of Medicine, Pulmonary, Allergy and Critical Care Division. "Our current study demonstrates that dietary flaxseed, already known for its strong antioxidant and anti-inflammatory properties, works as both a mitigator and protector against radiation pneumonopathy."

In several separate experiments, the researchers fed one group of mice a diet supplemented with 10 percent flaxseed, either three weeks before a dose of X-ray radiation to the thorax or two, four, or six weeks after radiation exposure. A control group subjected to the same radiation dose was given the same diet but receiving an isocaloric control diet without the flaxseed supplement. After four months, only 40 percent of the irradiated control group survived, compared to 70 to 88 percent of the irradiated flaxseed-fed animals. Various studies of blood, fluids, and tissues were conducted.

Dr. Christofidou-Solomidou and her colleagues found that the flaxseed diet conferred substantial benefits regardless of whether it was initiated before or after irradiation. Mice on flaxseed displayed improved survival rates and mitigation of radiation pneumonitis, with increased blood oxygenation levels, higher body weight, lower pro-inflammatory cytokine levels, and greatly reduced pulmonary inflammation and fibrosis.

The latter finding is especially exciting, because while radiation-induced inflammatory damage can be potentially treated with steroidal therapy (in radiotherapy patients for example), lung fibrosis is essentially untreatable. "There's nothing you can give to patients to prevent fibrosis," Dr. Christofidou-Solomidou points out. "Once a lung becomes "stiff" from collagen deposition, it's irreversible. We have discovered that flaxseed not only prevents fibrosis, but it also protects after the onset of radiation damage."

Dr. Christofidou-Solomidou and her colleagues are focusing further research on the bioactive lignan component of flaxseed, known as SDG (secoisolariciresinol diglucoside), which is believed to confer its potent antioxidant properties. The lignan component also "regulates the transcription of antioxidant enzymes that protect and detoxify carcinogens, free radicals and other damaging agents", she says.

Flaxseed boasts many other qualities that make it particularly attractive as a radioprotector and mitigator. "Flaxseed is safe, it's very cheap, it's readily available, there's nothing you have to synthesize," Dr. Christofidou-Solomidou notes. "It can be given orally so it has a very convenient administration route. It can be packaged and manufactured in large quantities. Best of all, you can store it for very long periods of time." That makes it especially interesting to government officials looking to stockpile radioprotective substances in case of accidental or terrorist-caused radiological disasters.

Learn more about research at Penn Med here