Late senator Hubert H. Humphrey was one of thousands of cancer victims who are "unnecessarily" undernourished in their last days, often crippling their efforts to fight the disease, a Harvard surgeon charged yesterday.

"Failure to capitalize on current developments in nutrition therapy" often undermines other therapies, and the federal government's National Cancer Institute is doing little to change this situation, Dr. George L. Blackburn told a Senate nutrition subcommittee.

Blackburn is a distinguished surgeon and head of a nutrition support service at New England Deaconess Hospital in Boston.

Humphrey's last doctor - the equally distinguished University of Minnesota surgery chief, John S. Najarian - said in Minneapolis that Blackburn is right about the need for proper nutrition in most cancer patients.

But Najarian said Blackburn was 100 percent wrong about Humphrey in his last days.

"Hubert Humphrey died of his cancer and nothing else and certainly not of malnutrition," Najarian said.

"We could have done one of two things in his final weeks," he explained further.

"We could have kept him in the hospital day and night and fed him intravenously, so when he died he perhaps wouldn't have been as thin. Or we could let him die at home, unencumbered by intravenous feeding.

"I talked it all over with him, and that's what we did."

Intravenous feeding - by tube through a blood vessel - is just what Blackburn said is needed in the many cancer patients who can't eat properly because anticancer chemicals make them ill.

What these patient require, he said, is a full array of nutrients, which can be given by tube in the form of amino acids (which make protein), carbohydrates, fats, minerals and vitamins.

"I'm not saying lack of proper nutrition affected Humphrey's survival," Blackburn said. "But many patients are unnecessarily depressed, weak and confined to bed.

"In bladder, ovarian, colon, stomach and pancreatic cancer, studies show pretty well that about 10 percent of all patients are unnecessarily undernourished. A third to a half of these might respond better to treatment if they were better nourished."

The same is true in several other forms of cancer, he said.

Less than $2 million of the National Cancer Institute's $881 million budget is devoted to nutrition of cancer patients, with another $2 million for other nutritional research, "adding up to half of 1 percent of the whole budget, hardly a justifiable contribution," Blackburn said.

Subcommittee Chairman George McGovern (D.-S.D.) credited the institute with spending "1 percent of its funds on diet/cancer research," NCI funds often are added up differently in different analyses. But McGovern called even the larger figure "a total failure" to address the diet-cancer problem, including the possibilities that proper diets may help prevent cancers and that improper diets may cause them.

Directors of the National Institutes of Health and NCI are expected to strike a middle ground in testimony today, defending most past priorities but conceding a need for some new directions.

The problem, McGovern said, is that "there is no indication of any increase in nutrition spending through 1983." In fact, Blackburn said, "there are only three people in the whole cancer institute with nutritional knowledge and there is no chance of anything more happening unless Congress acts."

Both Senate and House health subcommittees are planning further looks at the cancer institute and NIH, in particular at the directions of the multibillion-dollar "war on cancer" ordered by Congress in 1971.