Two More Reasons to Hug Your Beekeeper
by Douglas Page© 2002
We already know honey has no fat or cholesterol, provides quick energy, and can be stored indefinitely without refrigeration. Now, new research provides two more reasons to hug your beekeeper.
The studies, both from the University of Illinois, focused on the oxidation-inhibiting qualities of honey - one on cooked meat, the other on human blood. Oxidation is not good in either case.
Oxidation of meat degrades the flavor, but, more importantly, oxidation of blood contributes to heart disease. Long-term consumption of oxidized foods is implicated in aging and health problems because oxidation proceeds through a free radical process. Oxidation of lipoprotein (LDL) in the blood (the ‘bad’ cholesterol) is thought to play an important role in the development of hardening of the arteries (atherosclerosis). Increasing LDL’s resistance to oxidation is thought to possibly delay the progression of the disease.
"Free radicals are known to attack other molecules, such as proteins or DNA," said principal researcher Nicki Engeseth, professor of food chemistry at the University of Illinois. "As a result you can get a higher incidence of cardiovascular disease and cancer."
The idea behind Engeseth’s research is the use of honey - a natural source of antioxidants - in food systems to retard oxidation, preserve flavor and color, and give consumers fresher foods.
Previous Engeseth work demonstrated that honey was effective at reducing browning in sliced fruits and vegetables, which is caused by a form of oxidation called polyphenol oxidase. So she wondered what effect honey might have on lipid oxidation in meat systems.
She tested this by mixing 5 percent honey to fresh ground meat before cooking. The classic problem with cooked refrigerated or pre-cooked frozen meats is it develops a taste called ‘warmed-over flavor’, a loss in flavor quality caused by lipid oxidation. Engeseth wanted to see if she could minimize lipid oxidation by the addition of honey. Turkey, poultry, and ham products are all complementary to honey flavor.
"Honey is positive for flavor in most cases, but not all," said Joseph G. Sebranek, professor of Animal Science at Iowa State University, and president of the American Meat Science Association. "It works well in breakfast sausage for instance, but probably wouldn't be too well received on hamburgers."
Engeseth found that adding honey to ground turkey and holding it three days in the refrigerator significantly reduced oxidation. Also, when measured against traditional commercial preservatives such as butylated hydroxytoluene (BHT), honey at a comparable concentration was much more protective against oxidation.
Such encouraging results lead her next to examine the ability of honey to protect against oxidation in human blood serum. This work, published April 6 in the Journal of Agricultural & Food Chemistry, is the first to look at the effect of honey on human blood.
Engeseth collected blood samples from people working in her lab and used honey in different concentrations from different floral sources to see if it could protect against LDL oxidation.
"The reason that's so important is because it's believed that LDL oxidation is the initiating factor for atherosclerosis," she said. "When you oxidize LDL you actually initiate plaque deposition in the arteries. By being able to reduce the oxidation of LDL you theoretically should be able to reduce the incidence of plaque, or at least slow it down."
The honey worked.
Using a popular tool called Oxygen Radical Absorption Capacity (ORAC) that measures total serum antioxidant activity, Engeseth found the antioxidant capacity of honey to be equal to that in many fruits and vegetables in its ability to counter the degenerating activity of free radicals. "On a per gram basis, the antioxidant capacity of fruits and vegetables, as measured in ORAC units, is usually between .5 and 19. Of the seven honeys we tested (acacia, buckwheat, clover, fireweed, Hawaiian Christmas berry, soybean, and tupelo), we found a range of 3 to 16 ORAC units," Engeseth said.
"It still is too early to say definitively, but honey seems to have the potential to serve as a dietary antioxidant," she said. "Even though honey might not be consumed at the same gram level as fruits or vegetables, the potential is there."
Interestingly, in both studies Engeseth found that dark-colored honey, particularly buckwheat, provided more protective antioxidant punch than lighter-colored honeys. Engeseth examined a number of sources of buckwheat honey. Most had ORAC values between nine and 11, although one registered almost 17.
"So far, we don't really know what specifically is different about buckwheat honey, except that it's higher in phenolics," Engeseth said. Phenolics are compounds believed to be produced as a result of the plant's interaction with the environment, and seem to be the most highly correlated with antioxidant capacity.
Follow-up honey studies, either in progress or in the wings, should shed more light on the exact phenolic compounds in honey and on how effectively consumed honey prevents oxidation in the blood of human subjects.