UF Tests: Experimental Nutrition Product Boosts Immune Function And Reduces Flu Symptoms In Elderly

January 13, 2004

GAINESVILLE, Fla. — As influenza continues to take its toll, a new study by University of Florida researchers shows that nutrition can help seniors better weather the flu season.

“In a flu season like this one, we need every advantage we can get,” said Bobbi Langkamp-Henken, an associate professor at UF’s Institute of Food and Agricultural Sciences. “The real lesson here is that every senior should pay attention to their nutrition and realize that it affects their resistance to infection.”

Langkamp-Henken led a team of researchers from UF; the Veterans Affairs Medical Center in Gainesville; Drexel University in Philadelphia, Pa.; and Abbott Laboratories’ Ross Products Division in Columbus, Ohio, in a study to determine whether an experimental nutritional supplement would reduce in older people the number of days of symptoms of upper respiratory tract infection. Results of the study were published this month in the Journal of the American Geriatrics Society.

Influenza kills an average of 36,000 Americans every year, according to the Centers for Disease Control and Prevention. Older people are particularly at risk because immune function tends to decline with age. Even the flu shot – the strongest line of defense against the flu – tends to be less effective in older people due to declining immune function.

The researchers followed older people, all of them living at assisted or independent living facilities in North Central Florida, through the 1999-2000 flu season.

Participants were divided into two groups. One group was asked to drink a daily 360-calorie serving of an experimental product containing an enhanced blend of vitamins, minerals, antioxidants, proteins, indigestible carbohydrate – important for gastrointestinal health – and structured lipids, which provide energy and increase the absorption of nutrients. he other group was asked to take a control supplement that was similar in protein and energy content to the experimental supplement, though it contained smaller amounts of vitamins and minerals than were found in the experimental supplement.

Participants were asked to stop taking any vitamins or nutritional supplements they had been taking before the study began, and all were asked to take a daily low-potency vitamin – one originally intended for children – that provided about one-third of the Recommended Dietary Allowance of various vitamins and minerals. Together, the control supplement and the vitamin pill contained roughly the same vitamin and mineral content one would find in a typical 360-calorie meal.

“We couldn’t just give the control group empty calories,” she said. “It wouldn’t be fair to them. And we weren’t out to prove simply that our supplement was better than a poor diet. We wanted to show that this experimental supplement offered an advantage over the nutrition the participants would presumably get in a typical diet.”

Langkamp-Henken, an expert in nutritional immunology, said all participants were given the flu vaccine two weeks after the study began. They were monitored for six months, from October to April, and tested for their response to the vaccine and the number of days of symptoms of upper respiratory tract infections. Thirty-four participants, having an average age of 83, remained in the study for its full six-month duration.

Over the course, the researchers did blood tests on the participants looking for influenza antibodies. Eighty-seven percent of the 18 participants who drank the experimental supplement showed a fourfold increase in antibody titers and antibody titers over 40 – signs that indicate an individual is responding well to the flu vaccine. Only 35 percent of the participants in the control group showed the same responses.

Participants who drank the experimental formula also reported half as many days of flu-like symptoms – 78 days – than those who drank the control formula – 156 days.

Scientists have known for decades that single-nutrient deficiencies can suppress response to vaccines, but this is one of only a handful of studies that have examined the connection between nutrition and actual days of illness in seniors.

“This study is different from most in that we found nutrition to impact clinical outcomes not just immune function,” Langkamp-Henken said.

More importantly, the study emphasizes that as older people get a yearly flu shot they can also improve their response to the vaccine through good nutrition.

“In theory, you should get all the vitamins you need through a balanced diet, but the reality is that people aren’t always able to do that consistently,” Langkamp-Henken said. “Supplemental nutrition is the best way to make sure you’re filling in the gaps.”

And there are indications, Langkamp-Henken said, that many seniors don’t take multivitamins or supplemental nutrition. Of the 34 people who completed the study, only 12 reported regularly taking multivitamins before the study began.

“Although the liquid nutritional product we tested is not commercially available, multivitamin and mineral supplements are plentiful. Taking an adult-strength multivitamin, mineral supplement is inexpensive and easy to do,” Langkamp-Henken said. “If you can give seniors an immune advantage year around as well as during the cold and flu season, you should do it.”

The UF team also included Dr. Bradley Bender, a professor in the College of Medicine; Joyce Stechmiller, an associate professor in the College of Nursing and chairwoman of the college’s department of adult and elderly nursing; and Kelli Herlinger-Garcia, a senior biological scientist in the College of Agricultural and Life Sciences.