We all know the importance of breast milk for babies, but could it have a benefit for grownups too? 

Some people think so. A growing number of people are turning to mother's milk as a cancer treatment, including Howard Cohen.

After being diagnosed with prostate cancer, Cohen came across some Swedish research that found a protein in mother's milk killed cancer cells in petri dishes.

"This became a very interesting prospect," Cohen said.

He decided to give it a try. Making smoothies has become routine for him. They contain fruit, yogurt and breast milk.

"If you drink it straight, it has a bit of a yucky, oily under-taste," he said.

At first, Cohen got his supply from a friend who was breastfeeding. Now, he relies on a milk bank, which is similar to a blood bank. A doctor's prescription is required.

"We're noticing an increase in the number of patients who are adults and children who have a variety of types of cancer who are using human milk," said Pauline Sakamoto, of Mothers' Milk Bank.

This milk bank alone has supplied about 60 cancer patients.

"It may not mean that the cancer is cured, but we are seeing a dramatic change in the quality of life for some of them," Sakamoto said.

Leading specialists say: Hold on. While the Swedish research is interesting, there's not enough scientific proof.

"I do think that it's premature for adults to be drinking breast milk," said David Newburg, of Massachusetts General Hospital. "It hasn't been fully tested yet and we like to be very careful not to use things in humans that we don't understand."

Doctor Pamela Berens, of the Academy of Breastfeeding Medicine, worries that adults using donor milk will deplete an already limited supply.

"Right now we don't have enough breast milk for our donor milk banks for the premature infants who we have such wonderful data about the benefits," she said.

Proven benefits or not, Cohen is such a believer that when his own cancer doctor wouldn't give him a prescription, he found a doctor who would.

Breast milk from a milk bank runs an average of $3 an ounce. Insurance does not cover the costs for adult consumption.