Nutrition Research & Information

Summaries and references to honey nutritional studies.

Comparison of Vitamin, Mineral and Antioxidant Levels in Raw and Processed Honey

Ropa Science Research

Research Project Funded by the National Honey Board – D. Ropa, 2012

This 2012 study examined the effects of commercial processing on the pollen and nutrient content of honey.  Processing reduced the pollen content of the honey, but did not affect the nutrient content.  The micronutrient profile of honey is not associated with its pollen content and is not affected by commercial processing.

The 2012 study and abstract with statistical analysis was presented at the Federation of American Societies for Experimental Biology (FASEB) Conference in Boston April 20-24, 2013.

Comparison of Mineral and Enzyme Levels in Raw and Processed Honey

Ropa Science Research

Research Project Funded by National Honey Board - D. Ropa, 2010

To ascertain just how much honey changes after it has been heated and filtered, the National Honey Board contracted with American Analytical Laboratories to test honey samples taken prior to processing and then after being processed.  The goal was to find out the degree to which the minerals, antioxidants and enzymes change after honey is sent through an industrial processing system.

This research shows a great deal of variability between samples from the same supplier as well as samples across suppliers. Because of this level of variation, it is difficult to draw more than general conclusions regarding the changes that occur to honey post-processing. However, processing is not a fully destructive process, as some consumers would have others believe. Heating and filtering honey does not completely eliminate all enzymes, nor does it have a negative effect on honey’s mineral and antioxidant levels.

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The Effect of Honey on the Growth of Bifidobacteria

Michigan State University
Research Project Funded by National Honey Board - Z. Ustunol, Ph.D., 2001

Bifidobacteria are part of a group of bacteria considered important to the health of the gastrointestinal tract (GI).  Clinical studies have associated other beneficial effects such as immune enhancement and anti-carcinogenicity with the presence of bifidobacteria in the GI tract.

One approach for ensuring or increasing the presence of healthful colonic bacteria is to provide them as a probiotic.  A probiotic is a live microbial feed supplement, which beneficially affects the host organism by improving its intestinal microbial balance.

Dairy products have been the preferred medium to reintroduce viable populations of lactic acid bacteria and bifidobacteria into the GI tract of both children and adults.  Bifidobacteria must remain viable in large numbers in the carrier food to be used with confidence as a dietary adjunct.  However, maintaining the viability of bifidobacteria during processing and refrigerated storage has been a challenge to dairy processors.

Another approach to increasing the numbers of bifidobacteria in the GI tract is the incorporation of prebiotics in the diet.  A prebiotic is a non-digestible dietary supplement that modifies the balance of the intestinal microflora stimulating the growth and/or activity of the beneficial organisms and suppressing potentially deleterious bacteria. Currently, the most common prebiotics are nondigestible oligosaccharides, such as fructooligosaccharides (FOS) and inulin.

Growth and viability of bifidobacteria in fermented milk can be enhanced significantly by the incorporation of FOS and galacto-oligosaccharides (GOS) in milk prior to fermentation.  Honey contains a variety of oligosaccharides varying in their degree of polymerization.  The unique composition of honey suggests that it could enhance the growth, activity and viability of bifidobacteria in milk and thus, fermented dairy products.  To evaluate this hypothesis, the following study on growth-promoting and prebiotic activity of honey on bifidobacteria was conducted.

Research Article Category: Honey and Prebiotics

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US honeys varying in glucose and fructose content elicit similar glycemic indexes

Journal of American Dietetic Association
Ischayek JI, Kern M., 2006 Aug; 106(8):1260-2

The predominant carbohydrates found in honey are glucose and fructose, the relative percentages of which depend largely on the floral variety. Research suggests that the fructose-to-glucose ratio in a given honey and, thus, its floral source, may influence the glycemic response and, thus, the glycemic index (GI). To date, no studies of examining the GI of US honey varieties are available. Thus the purpose of this study was to determine the GI of four US honey varieties (clover, tupelo, cotton, and buckwheat) differing in fructose-to-glucose ratio. Twelve healthy adult men and women with a mean (+/-standard error) age of 24.5+/-1.5 years served as subjects. The glycemic index of 250-mL solution servings of clover, buckwheat, cotton, and tupelo honeys providing 50 g carbohydrate were assessed relative to triplicate feedings of 50 g carbohydrate as a glucose solution. Fructose-to-glucose ratios were 1.09, 1.12, 1.03, 1.54, for clover, buckwheat, cotton, and tupelo, respectively. Blood was collected after an overnight fast and 15, 30, 45, 60, 90, and 120 minutes after intake. Ten minutes were allowed for food consumption. Areas under the glycemic response curves for each honey were expressed as percent means of each participant’s average response to glucose feedings. The means (+/-standard error) of the glycemic index were 69.2+/-8.1, 73.4+/-6.4, 73.6+/-6.6, 74.1+/-8.2 for clover, buckwheat, cotton, and tupelo honeys, respectively. No statistically significant differences between the honeys were apparent, nor was a relationship between glycemic index and the fructose-to-glucose ratio detected. These results indicate that small differences in fructose-to-glucose ratios do not substantially impact honey glycemic index.

Research Article Category: Miscellaneous

Frequent consumption of honey, tea and ham may be effective to improve selenium concentration

Annals of Nutrition and Metabolism
2004 May 6;48(3):134-140

Frequent consumption of honey, tea and ham may be effective to improve selenium concentration in selenium-inadequate individuals

Selenium has recently gained attention for its indirect, albeit important role as an antioxidant. Selenium is a component of glutathione peroxidases, a family of antioxidant enzymes that aid in preventing lipid peroxidation and membrane damage that can result from free radicals. Studies indicate the selenium status is highly dependent upon dietary sources of selenium which can be highly variable depending upon the selenium content of the soil from which the given food originates. The purpose of this study was to assess which foods or food groups best affect serum selenium in subjects with low selenium status (i.e., selenium concentrations < 70 microg/L). One hundred and twenty-nine subjects residing in Poland completed a semi-quantitative food frequency questionnaire. Serum selenium concentrations were determined using the electrothermal absorption spectrometry (ETAAS) technique following serum dilution. The consumption of ham, honey and tea was positively associated with the selenium concentration in the sera of selenium-inadequate subjects. In The selenium concentrations in the sera of the selenium-adequate subjects were positively correlated with the frequencies of wholegrain bread consumption and processed fruit consumption. These results suggest that frequent consumption of ham, tea and honey may be effective to improve the selenium concentration of selenium-inadequate subjects.

Research Article Category: Miscellaneous

Acute and Chronic Effects of Honey and Its Carbohydrate Constituents on Calcium Absorption in Rats

Journal of Agricultural and Food Chemistry
Ariefdjohan, Martin, Lachcik, and Weaver: 2008, 56, 2649–2654

The effects of honey and its carbohydrate constituents (glucose, fructose, and raffinose) on calcium absorption in rats were investigated in acute and chronic feeding studies. In the acute study, rats (n=120) were gavaged with an oral solution consisting of (a) 10 µCi Ca, (b) 25 mg of calcium as calcium acetate, and (c) one of the following: 0 mg of honey (control), or 200, 500, or 800 mg of honey, a glucose fructose mixture, 10.75 mg of raffinose, or 200 mg of raffinose. Another group received Ca intraperitoneally. Femurs were collected 2 days later and analyzed for Ca content. Rats given 500 and 800 mg of honey showed 25.5 and 33.6% increases in calcium absorption (P < 0.05), respectively, over the control group. Groups given the glucose fructose mixture or 200 mg of - raffinose had a significantly higher increase in calcium absorption than the control group (17.1 and 25.6%, respectively). In the chronic study, rats (n 96) were fed for 8 weeks with either 0% honey (control), 5% honey, 10% honey, or a glucose fructose raffinose (GFR) mixture. Femurs of GFR-fed rats had significantly lower calcium content, Ca absorption, width, and BMD (at distal region) than control rats. Groups fed honey did not show the negative effects of GFR on bone, but had no advantage over the control group. No significant differences were observed in femur length, density, strength, or BMC among any treatment group compared to the control group. These results indicate that although a positive dose–response effect of honey and its carbohydrate constituents on calcium absorption was observed in the acute study, this effect disappeared upon long-term feeding in rats, implying adaptation had occurred.

Research Article Category: Miscellaneous

Honey enhances the production of lactic acid from Bifidobacteria

Journal of Food Science

Lactic acid bacteria are common starter cultures used by the dairy industry to manufacture fermented dairy products (i.e., yogurt). Honey may be an ideal sweetener for yogurt due to its sugar concentration, pH, and value-added image. Nonetheless, manufacturers have been reluctant to use honey as a sweetener in yogurts due to the belief that honey may be inhibitory to lactic acid starter cultures. The purpose of this study was to examine the growth of lactic acid bacteria and bifidobacteria in a honey medium and determine the levels of lactic and acetic acid produced by these organisms when grown in honey. Twelve percent nonfat dry milk containing 5% (w/w) clover honey, fructose or sucrose were pasteurized and inoculated with commercial strains of Steptococcus thermophilus, Lactobacillus delbrukeii subsp bulgaricus and probiotics Lactobacillus acidophilus and Bifidobacterium bifidum. Samples were examined at 0 and 24 hours for (1) viability of bacteria and (2) levels of fermentation end products (i.e., lactic and acetic acid). Viability of bacteria was not influenced by sweetener type indicating that honey was not inhibitory at the 5% level. In addition, honey significantly enhanced the growth/production of lactic acid from Bifidobacteria. These results indicate that honey could be a suitable sweetener for fermented dairy products such as yogurt.

Research Article Category: Honey and Prebiotics

Honey Can Serve as an Effective Carbohydrate Replacement During Endurance Exercise

Journal of Strength and Conditioning Research

The benefit of CHO consumption during endurance exercise is well-documented. It is generally recommended that a high glycemic index (GI) carbohydrate (CHO) be used; although data supporting this recommendation is limited. The purpose of this study was to compare a high GI CHO (glucose) to a lower GI CHO (honey) on cycling performance. Nine male endurance athletes participated in 3 simulated 64 km time trials with a 7-day washout period between trials. Supplements—honey, glucose, placebo—were provided randomly and double-blind at the beginning of the TT and every 16 km thereafter. Power output (Watts), HR, RPE, glucose, insulin and time to complete the segment were measured every 16 km. Time to complete the total TT was significantly faster for the both the glucose and honey groups compared to the placebo group (p < 0.05) largely due to a longer time for the placebo group to complete the last two 16 km. Power output was significantly greater for the honey and glucose groups vs. the placebo group (p < 0.05); however, when the final 16-km power output was expressed as a percentage of pretest maximal power output, only the glucose treatment was greater than placebo (although the honey condition approached significance (p < 0.06)).

Research Article Category: Sports Nutrition

Honey can enhance the growth and acid production of human Bifidobacterium ssp.

Journal of Food Protection

The study examined the potential for honey to act as a pre-biotic, i.e., enhance the growth of and promoting lactic and acetic acid production by human intestinal Bifidobacteria. Five human intestinal Bifidobacterium spp., (B. longum, B. adolescentis, B. breve, B. bifidum, and B. infantis), were cultured in reinforced clostridial medium (control) and in reinforced clostridial medium supplemented with 5% (wt/vol) clover honey, fructooligosaccharide (FOS), galactooligosaccharide (GOS), or inulin. Inoculated samples were incubated anaerobically at 37degrees C for 48 h. Samples were collected at 12-h intervals (i.e., 12, 36, and 48 hr) and examined for specific growth rate. Levels of fermentation end products (lactic and acetic acids) were measured by high-pressure liquid chromatography. Honey, FOS, GOS, and inulin showed similar effectiveness in supporting Bifidobacterium spp growth and were significantly more effective than the control at 36 and 48 hr (P < 0.05).

Research Article Category: Honey and Prebiotics

Identification and Quantification of Antioxidant Components of Honeys from Various Floral Sources

Journal of Agricultural and Food Chemistry
2002, Vol. 50, No. 21, pp.5870-5877

The objective of this study was to quantify and characterize the antioxidants and some of the isolated phenolic compounds and/or fractions of honeys from seven different floral sources (acacia, buckwheat, clover, fireweed, Hawaiian Christmas berry, tupelo, and soybean). Chromatograms of the phenolic nonpolar fraction of the honeys indicated that most honeys contain similar types but quantitatively different phenolic contents. The primary flavinoids identified were the flavanones pinobanksin, and pinocembrin and the flavones chrysin and galangin. A linear correlation between phenolic content and ORAC activity was demonstrated (R(2) = 0.963, p < 0.0001). Honeys were separated by solid-phase extraction into four fractions to identify the relative contribution of each fraction to the antioxidant activity of honey. Antioxidant analysis of the different honey fractions suggested that the water-soluble fraction contained most of the antioxidant components, including protein; gluconic acid; ascorbic acid; hydroxymethylfuraldehyde; and the combined activities of the enzymes glucose oxidase, catalase and peroxidase. Of these components, a significant correlation could be established only between protein content and ORAC activity (R(2) = 0.674, p = 0.024). These results suggest that the antioxidant capacity of honey is a product of the combined activity of a wide range of compounds including phenolics, peptides, organic acids, enzymes, Maillard reaction products, and possibly other minor components.

Research Article Category: Honey and Antioxidants

Antioxidant capacity of honeys from various floral sources

Journal of Agricultural and Food Chemistry

Antioxidant capacity of honeys from various floral sources and inhibition of in vitro lipoprotein oxidation in human serum samples
In this study honeys from seven different floral sources (acacia, buckwheat, clover, fireweed, Hawaiian Christmas berry, tupelo, and soybean) were analyzed for in vitro antioxidant capacity and total phenolic content. Antioxidant capacity was measured by the oxygen radical absorbance capacity (ORAC) assay and by monitoring the formation of conjugated dienes as an index of the inhibition of copper-catalyzed serum lipoprotein oxidation. ORAC values for the honeys ranged from 3.0 micromol Trolox equivalent/g for acacia to 17.0 micromol Trolox equivalent/g for buckwheat and all were significantly higher than the sugar analogue (p < 0.05). A linear correlation was observed between phenolic content and ORAC activity of the investigated honeys (p < 0.0001, R (2) = 0.9497). The relationship between the ORAC activity and inhibition of lipoprotein oxidation by the honeys yielded a correlation coefficient of 0.6653 (p = 0.0136). This work shows that honey may serve as a source of dietary antioxidants and a healthy alternative to sugar.

Research Article Category: Honey and Antioxidants

Honeys with high phenolic contents can increase serum antioxidant capacity in healthy human subjects

Journal of Agricultural and Food Chemistry

The effects of consuming 1.5 g/kg body weight of corn syrup or buckwheat honey on the antioxidant and reducing capacities of plasma. Forty subjects were randomly assigned to one of four groups: (1) corn syrup, (2) low phenolic content buckwheat honey, (3) high phenolic content buckwheat honey, (4) water. Following consumption of the two honey treatments, plasma total-phenolic content increased (P < 0.05) as did plasma antioxidant and reducing capacities (P < 0.05). In contrast, corn syrup had no significant effect. These data support the concept that phenolic antioxidants from processed honey are bioavailable, and that they increase antioxidant activity of plasma. It can be speculated that honey consumption could augment the body’s defenses against oxidative stress. Given that the average sweetener intake by humans is estimated to exceed 70 kg per year, the substitution of honey for traditional sweeteners could result in an enhanced antioxidant defense system in healthy adults.

Research Article Category: Honey and Antioxidants

Buckwheat Honey Increases Serum Antioxidant Capacity in Humans

Journal of Agricultural and Food Chemistry
2003, Vol. 51 pp. 1500-1505

This study examined the acute effects of consuming buckwheat honey (dissolved in water) compared to black tea, black tea with sugar, or black tea with buckwheat honey on serum oxidative status and lipoprotein oxidation. Twenty-five healthy men consumed each of the five beverages in a blind, randomized fashion. Antioxidant capacity of human serum samples was measured using a variety of methods including the oxygen radical absorbance capacity (ORAC) assay, ex vivo susceptibility of serum lipoprotein to Cu(2+)-induced oxidation, and the thiobarbituric acid reactive substances (TBARS) assay. The results showed that black tea with honey had the highest phenolic content and thus antioxidant potential, followed by tea alone, tea with sugar and honey alone. However, buckwheat honey produced the greatest increase in serum antioxidant capacity (demonstrating the inconsistency between the antioxidant potential of a food and its actual effect on serum antioxidant capacity). Ex vivo serum lipoprotein oxidation and TBARS values were not significantly altered after consumption of any of the five beverages.

Research Article Category: Honey and Antioxidants

Chronic Honey Consumption Increases Plasma Antioxidant Concentration

Abstract presented at the American Chemical Society
March 29, 2004

Gross H. Effect of honey consumption on plasma antioxidant status in human subjects.

Previous research has indicated that a acute honey consumption (i.e., a single dose) can raise the phenolic concentration of the plasma. This study examined the effects of chronic honey consumption to determine if increases in total plasma phenolic content and plasma antioxidant capacity could be sustained over the long term. Twenty-five subjects (13 Males and 12 females) consumed 1.5 grams of honey per kilogram of body weight (~4-10 tablespoons) for 28 days. Subjects were randomly assigned either a honey with a high phenolic content (HA) or a lower phenolic content (LA). Total plasma phenolics were measured on day 1 and 29 at 5 different time points: immediately after honey consumption and then again 1.5 hr, 3 hr 6 hr and 24 hour post-consumption. The results indicated that the phenolic content of the plasma on day 29 was significantly higher than baseline (i.e., day one) in both honey groups, suggesting that chronic honey consumption can increase the antioxidant capacity of the plasma.

Research Article Category: Honey and Antioxidants

Effect of Processing and Storage on Antioxidant Capacity of Honey

Journal of Food Science

Commercial honey processing generally involves controlled heating (to destroy yeast and delay granulation) combined with fine straining or pressure filtration. There has been concern that the processing of honey may reduce the antioxidant capacity of honey. This study examined the impact of heat and filtration on the antioxidant capacity of clover and buckwheat honeys during storage. Processed and unprocessed clover and buckwheat honey was stored in clear glass, amber glass, and polyethylene bottes and stored at room temperature under both natural laboratory lighting and in the dark (3 samples per condition). Additional samples were stored for 6 months at 4 degrees Celsius and -20 degrees Celsius. Antioxidant capacity of the honeys was determined by oxygen radical absorbance capacity (ORAC). Processing clover did not significantly impact antioxidant capacity; however, processing lowered the antioxidant capacity for buckwheat honey, by 33.4%. Antioxidant capacity of all honey samples was reduced after 6 months storage, with no impact of storage temperature or container type. Processed and raw honeys showed similar antioxidant capacity after storage.

Research Article Category: Honey and Antioxidants

Total Antioxidant Content of Alternatives to Refined Sugar

2009; 109:64-71

Background: Oxidative damage is implicated in the etiology of cancer, cardiovascular disease, and other degenerative disorders. Recent nutritional research has focused on the antioxidant potential of foods, while current dietary recommendations are to increase the intake of antioxidant– rich foods rather than supplement specific nutrients. Many alternatives to refined sugar are available, including raw cane sugar, plant saps/syrups (eg, maple syrup, agave nectar), molasses, honey, and fruit sugars (eg, date sugar). Unrefined sweeteners were hypothesized to contain higher levels of antioxidants, similar to the contrast between whole and refined grain products.

Objective: To compare the total antioxidant content of natural sweeteners as alternatives to refined sugar.
Design: The ferric-reducing ability of plasma (FRAP) assay was used to estimate total antioxidant capacity. Major brands of 12 types of sweeteners as well as refined white sugar and corn syrup were sampled from retail outlets in the United States.

Results: Substantial differences in total antioxidant content of different sweeteners were found. Refined sugar, corn syrup, and agave nectar contained minimal antioxidant activity (0.01 mmol FRAP/100 g); raw cane sugar had a higher FRAP (0.1 mmol/100 g). Dark and black–strap molasses had the highest FRAP (4.6 to 4.9 mmol/ 100 g), while maple syrup, brown sugar, and honey showed intermediate antioxidant capacity (0.2 to 0.7 mmol FRAP/100 g). Based on an average intake of 130 g/day re?ned sugars and the antioxidant activity measured in typical diets, substituting alternative sweeteners could increase antioxidant intake an average of 2.6 mmol/day, similar to the amount found in a serving of berries or nuts.

Research Article Category: Honey and Antioxidants