The effects of conjugated linoleic acid supplementation on immune function in healthy volunteers

OBJECTIVE: To assess the effects of dietary supplementation using two isomeric blends of conjugated linoleic acid (CLA) on immune function in healthy human volunteers. DESIGN: Double-blind, randomised, placebo-controlled intervention trial. SUBJECTS AND INTERVENTION: A total of 55 healthy volunteers (n=20 males, n=35 females) were randomised into one of three study groups who received 3 g/day of a fatty acid blend containing a 50:50 cis-9, trans-11: trans-10, cis-12 CLA isomer blend (2 g CLA), and 80:20 cis-9, trans-11: trans-10, cis-12 (80:20) CLA isomer blend (1.76 g CLA) or linoleic acid (control, 2 g linoleic acid) for 8 weeks. RESULTS: Supplementation with the 80:20 CLA isomer blend significantly (P< or =0.05) enhanced PHA-induced lymphocyte proliferation. CLA decreased basal interleukin (IL)-2 secretion (P< or =0.01) and increased PHA-induced IL-2 and tumor necrosis factor alpha (TNF(alpha)) production (P< or =0.01). However, these effects were not solely attributable to CLA as similar results were observed with linoleic acid. CLA supplementation had no significant effect on peripheral blood mononuclear cells IL-4 production, or on serum-soluble intercellular adhesion molecule-1 (sICAM-1) or plasma prostaglandin E2 (PGE2) or leukotreine B4 (LTB4) concentrations. CONCLUSIONS: This study shows that CLA supplementation had a minimal effect on the markers of human immune function. Furthermore, supplementation with CLA had no immunological benefit compared with linoleic acid.     

Effect of CLA supplementation on immune function in young healthy volunteers

OBJECTIVES: This study investigated the effect of dietary CLA supplementation (3g/day; 50:50 mix of the two major isomers) on the immune system and plasma lipids and glucose of healthy human (male and female) volunteers. DESIGN: Double-blind, randomized, reference-controlled study. SUBJECT AND INTERVENTION: A total of 28 healthy male and female participants aged 25-50 y received either high oleic sunflower oil (reference) or 50% CLA 9-11 and 50% CLA 10-12 CLA isomers (50:50 CLA-triglyceride form). The treatments were given as supplements in soft-gel capsules providing a total 3 g (6 x 500 mg capsules) per day in treatment groups for 12 weeks. A 12-week washout period followed the intervention period. RESULTS: Levels of plasma IgA and IgM were increased (P < 0.05 and 0.01 respectively), while plasma IgE levels were decreased (P < 0.05). CLA supplementation also decreased the levels of the proinflammatory cytokines, TNF-alpha and IL-1beta (P < 0.05), but increased the levels of the anti-inflammatory cytokine, IL-10 (P < 0.05). Another aspect of immune function, delayed type hypersensitivity (DTH) response, was decreased during and after CLA supplementation (P < 0.05). However, plasma glucose, lipids, lymphocyte phenotypic results were not affected significantly by CLA. CONCLUSION: This is the first study to show that CLA, a fatty acid naturally found in dairy and meat products, can beneficially affect immune function in healthy human volunteers. SPONSORSHIP: This study was supported by Loders-Croklaan, The Netherlands and SEERAD (Scottish Executive Environmental Rural and Agriculture Department).     

Effects of soybean peptide on immune function, brain function, and neurochemistry in healthy volunteers

ObjectiveSoybeans, an excellent source of dietary peptides, have beneficial effects on health. We investigated the effect of the soybean peptide on immune function, brain function, and neurochemistry in healthy volunteers.MethodsNear-infrared spectroscopy (NIRS) was used to analyze brain cerebral blood flow. The A and DA levels in the serum were analyzed by ELISA kit. The total number of leukocytes was recorded with a standard counter. Flow cytometry was used to assess lymphocyte subset levels.ResultsCell numbers were upregulated in the group that had fewer leukocytes but downregulated in the group with more leukocytes. For the lymphocyte-rich type, lymphocyte counts tended to decrease, accompanied by an increase in granulocyte numbers. For the granulocyte-rich type, granulocyte counts tended to increase, but lymphocyte counts also increased. The numbers of CD11b⁺ cells and CD56⁺ cells increased significantly. Soybean peptide decreased the adrenalin level in plasma but increased the level of dopamine. Near-infrared spectroscopy showed significant increases in the amplitudes of θ, α-2, and β-L frequency bands after the ingestion of peptides.ConclusionSoybean peptides can modulate cellular immune systems, regulate neurotransmitters, and boost brain function.     

Dose-response effects of fish-oil supplementation in healthy volunteers

We performed a randomized, controlled study on the dose-response effects of daily supplementation of 1.5, 3, and 6 g of the marine fatty acids eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) as their ethyl esters for 12 wk in 45 healthy normotriglyceridemic male volunteers. Significant dose-related increases of the n-3 fatty acids 20:5, 22:5, and 22:6 in plasma phospholipids (p less than 0.0001) were found, corresponding roughly to decreases of the n-6 fatty acids 18:2 and 20:4 (p less than 0.001). Serum triglycerides and HDL3-cholesterol concentrations showed a dose-dependent reduction (p less than 0.05) and HDL2 cholesterol increased (p less than 0.05). Results for 3 and 6 g n-3 fatty acids were similar. No dose-dependent effects were observed in the VLDL-, LDL-, and total HDL-cholesterol subfractions; blood pressure; bleeding time; erythrocyte deformability; or capacity of polymorphonuclear leukocytes to kill Staphylococcus aureus. This study indicates that 3 g n-3 ethyl ester fatty acids appears to be the appropriate supplementation dose in humans, at least regarding lipid-profile changes and the ability to incorporate such fatty acids in the plasma phospholipids.     

Effects of isomalt consumption on gastrointestinal and metabolic parameters in healthy volunteers

The polyol isomalt (Palatinit) is a well established sugar replacer. The impact of regular isomalt consumption on metabolism and parameters of gut function in nineteen healthy volunteers was examined in a randomised, double-blind, cross-over trial with two 4-week test periods. Volunteers received 30 g isomalt or 30 g sucrose daily as part of a controlled diet. In addition to clinical standard diagnostics, biomarkers and parameters currently discussed as risk factors for CHD, diabetes or obesity were analysed. Urine and stool Ca and phosphate excretions were measured. In addition, mean transit time, defecation frequency, stool consistency and weight were determined. Consumption of test products was affirmed by the urinary excretion of mannitol. Blood lipids were comparable in both phases, especially in volunteers with hyperlipidaemia, apart from lower apo A-1 (P=0.03) for all subjects. Remnant-like particles, oxidised LDL, NEFA, fructosamine and leptin were comparable and not influenced by isomalt. Ca and phosphate homeostasis was not affected. Stool frequency was moderately increased in the isomalt phase (P=0.006) without changes in stool consistency and stool water. This suggests that isomalt is well tolerated and that consumption of isomalt does not impair metabolic function or induce hypercalciuria. In addition, the study data indicate that isomalt could be useful in improving bowel function.     

Acute effects of exposure to air contaminants in a sawmill on healthy volunteers.

OBJECTIVES: To study whether air contaminants in sawmills can induce acute changes in the upper and lower airways of previously non-exposed subjects. METHODS: Nineteen healthy volunteers were examined to find the concentration of interleukin 6 (IL-6) in nasal lavage fluid and lung function before and after five hour exposure to dusts and fumes generated in a sawmill where timber from Scots pine was sawed. When exposed, the subjects had respirators with and without a particle filter. RESULTS: The median for daily time weighted average concentration of total dust for subjects with respirators without a filter was 0.13 mg/m3, which was significantly higher than the median of 0.04 mg/m3 for subjects who had respirators with a filter. The median for the concentration of IL-6 in the nasal lavage fluid increased after exposure from 0.5 to 5.9 pg/ml in subjects with respirators without a particle filter (P < 0.05). The increase of the concentration of IL-6 was significantly correlated with the dust concentration. A decrease in transfer factor of the lung was significantly correlated with daily time weighted average concentrations of terpenes. CONCLUSION: The findings suggest that healthy volunteers, exposed to air contaminants in a sawmill, show a slight inflammatory reaction. Also, the results of the study indicate the importance of decreasing the concentrations of wood dust in the work environment.     

Sildenafil effects on sexual function in asymptomatic volunteers: a controlled study

In a naturalistic setting, sildenafil may affect quality, satisfaction, and the desire for intercourse in young asymptomatic men. Healthy men 21 years old or older having sex with a steady female partner for at least 6 months and intercourse frequency of at least twice a week were eligible. Subjects received 4 capsules of sildenafil powder 50 mg to take home for one 2-week period, to use one hour before sexual activity. For a second 2-week period, they received 4 identical placebo capsules. Ten subjects aged 22 to 34 were studied. The effects found in this study were small and of borderline statistical significance. The findings may be analogous to those with antidepressants, where major effects are seen only in clinically depressed patients, however, normal volunteers have subtle and difficult-to-measure effects.     

The influence of the call with a mobile phone on heart rate variability parameters in healthy volunteers

It is possible that electromagnetic field (EMF) generated by mobile phones (MP) may have an influence on the autonomic nervous system (ANS) and modulates the function of circulatory system. The aim of the study was to estimate the influence of the call with a mobile phone on heart rate variability (HRV) in young healthy people. The time and frequency domain HRV analyses were performed to assess the changes in sympathovagal balance in a group of 32 healthy students with normal electrocardiogram (ECG) and echocardiogram at rest. The frequency domain variables were computed: ultra low frequency (ULF) power, very low frequency (VLF) power, low frequency (LF) power, high frequency (HF) power and LF/HF ratio was determined. ECG Holter monitoring was recorded in standardized conditions: from 08:00 to 09:00 in the morning in a sitting position, within 20 min periods: before the telephone call (period I), during the call with use of mobile phone (period II), and after the telephone call (period III). During 20 min call with a mobile phone time domain parameters such as standard deviation of all normal sinus RR intervals (SDNN [ms]--period I: 73.94+/-25.02, period II: 91.63+/-35.99, period III: 75.06+/-27.62; I-II: p<0.05, II-III: p<0.05) and standard deviation of the averaged normal sinus RR intervals for all 5-mm segments (SDANN [ms]--period I: 47.78+/-22.69, period II: 60.72+/-27.55, period III: 47.12+/-23.21; I-II: p<0.05, II-III: p<0.05) were significantly increased. As well as very low frequency (VLF [ms2]--period I: 456.62+/-214.13, period II: 566.84+/-216.99, period III: 477.43+/-203.94; I-II: p<0.05), low frequency (LF [ms(2)]--period I: 607.97+/-201.33, period II: 758.28+/-307.90, period III: 627.09+/-220.33; I-II: p<0.01, II-III: p<0.05) and high frequency (HF [ms(2)]--period I: 538.44+/-290.63, period II: 730.31+/-445.78, period III: 590.94+/-301.64; I-II: p<0.05) components were the highest and the LF/HF ratio (period I: 1.48+/-0.38, period II: 1.16+/-0.35, period III: 1.46+/-0.40; I-II: p<0.05, II-III: p<0.05) was the lowest during a call with a mobile phone. The tone of the parasympathetic system measured indirectly by analysis of heart rate variability was increased while sympathetic tone was lowered during the call with use of a mobile phone. It was shown that the call with a mobile phone may change the autonomic balance in healthy subjects. Changes in heart rate variability during the call with a mobile phone could be affected by electromagnetic field but the influence of speaking cannot be excluded.     

Dose-related effects of eicosapentaenoic acid on innate immune function in healthy humans: a comparison of young and older men

BACKGROUND: Increasing intakes of long-chain n-3 polyunsaturated fatty acids (PUFAs) can decrease markers of immunity. However, dose- and age-related responses have not been identified. OBJECTIVE: The objective was to determine the effects of different amounts of eicosapentaenoic acid (EPA) on innate immune outcomes in young and older males. DESIGN: In a controlled, double-blind study, healthy young and older men consumed 1 of 4 supplements provided as capsules: placebo (corn oil) or different amounts of an oil providing 1.35, 2.7, or 4.05 g EPA/d for 12 wk. Blood samples were collected at baseline and after 12 wk. RESULTS: EPA was incorporated in a linear dose-response fashion into plasma and mononuclear cell (MNC) phospholipids; incorporation was greater in the older men. EPA treatment did not alter neutrophil or monocyte phagocytosis, monocyte respiratory burst, or the production of inflammatory cytokines by MNCs in the young or older men. EPA treatment caused a dose-dependent decrease in neutrophil respiratory burst only in the older men. Increased incorporation of EPA into plasma or MNC phospholipids was associated with decreased production of prostaglandin E2 by MNCs from both young and older men. CONCLUSIONS: Older subjects incorporate EPA into plasma and MNC phospholipids more readily than do younger subjects. Other than prostaglandin E2 production, innate immune responses in young subjects are not affected by an EPA intake of < or =4.05 g/d. Older subjects are more sensitive to the immunologic effects of EPA, and the neutrophil respiratory burst is lower at higher EPA intakes.     

LDL cholesterol-lowering effects of grape extract used as a dietary supplement on healthy volunteers

The aim of this study was to evaluate the effects of Eminol®, the polyphenol-rich grape extract supplement (700 mg), on cardiovascular risk and oxidant stress indicators in a sample of volunteers. A randomized, double-blind, placebo-controlled clinical trial was performed over 56 days and included 60 volunteers. Thirty volunteers took 700 mg of the grape extract, Eminol® (E), and 30 took the placebo (P). On comparison of the results, a decrease in total cholesterol (E: 213.77 ± 4.1 mg/dl and P: 245.57 ± 4.1 mg/dl; p = 0.01) and LDL cholesterol (E: 142.17 ± 3.1 mg/dl and P: 165.13 ± 3.1 mg/dl; p = 0.02) levels as well as an increase in antioxidant capacity (E: 65.63 ± 5.8 μmol TE/mg and P: 57.80 ± 7.7 μmol TE/mg; p < 0.01) and vitamin E (E: 11.46 ± 0.5 μg/ml and P: 9.06 ± 0.5 μg/ml; p = 0.018) was observed. This result indicates that the grape extract Eminol® modulated the lipid profile in terms of cardiovascular risk indicators, lowering total blood cholesterol and LDL cholesterol levels.     

Acute effects of beer on endothelial function and hemodynamics: A single-blind,crossover study in healthy volunteers

ObjectiveModerate consumption of beer is associated with lower cardiovascular (CV) risk. The goal of this study was to determine the effect of beer consumption on CV risk. To explore the underlying mechanisms, we studied the acute effects of the constituents of beer (alcohol and antioxidants), on established predictors of CV risk: endothelial function, aortic stiffness, pressure wave reflections and aortic pressure.MethodsIn a randomized, single-blind, crossover study, 17 healthy, non-smoking, men (ages 28.5 ± 5.2 y with body mass index 24.4 ± 2.5 kg/m²) consumed on three separate occasions, at least 1 wk apart: 1. 400 mL of beer and 400 mL water, 2. 800 mL of dealcoholized beer (same amount of polyphenols as in the 400 mL of beer), and 3. 67 mL of vodka and 733 mL water (same amount of alcohol as in the 400 mL of beer).Each time aortic stiffness (pulse wave velocity), pressure wave reflections (AΙx), aortic and brachial pressure (Sphygmocor device), and endothelial function (brachial flow mediated dilatation) were assessed at fast and 1 and 2 h postprandial.ResultsAortic stiffness was significantly and similarly reduced by all three interventions. However, endothelial function was significantly improved only after beer consumption (average 1.33%, 95% confidence interval [CI] 0.15–2.53). Although wave reflections were significantly reduced by all three interventions (average of beer: 9.1%, dealcoholized beer: 2.8%, vodka 8.5%, all CI within limits of significance), the reduction was higher after beer consumption compared with dealcoholized beer (P = 0.018). Pulse pressure amplification (i.e., brachial/aortic) was increased by all three test drinks.ConclusionsBeer acutely improves parameters of arterial function and structure, in healthy non-smokers. This benefit seems to be mediated by the additive or synergistic effects of alcohol and antioxidants and merits further investigation.     

Dietary protein precipitation properties have effects on gastric emptying in healthy volunteers

BACKGROUND & AIMS: Strategies that reduce the size of particles in the stomach accelerate gastric emptying. Partial dephosphorylation of casein reduces the size of protein precipitates (curds) in acid conditions and facilitates peptic digestion. We hypothesized that changing the precipitation properties of casein by partial dephosphorylation would accelerate gastric emptying. METHODS: Eight healthy male volunteers entered a prospective, double blind, randomized study with crossover design. Gastric emptying of milk based formula containing either unmodified or dephosphorylated casein was assessed by scintigraphy. Gastric pH measurements were acquired concurrently. RESULTS: A trend to faster gastric emptying was observed for the unmodified preparation, with lower median half time (unmodified 133; dephosphorylated 214 min, P = 0.09) and area under the curve (unmodified 8425 min%; dephosphorylated 9135 min%, P = 0.08). A positive correlation was found between half time for the dephosphorylated preparation and the treatment effect (r2 = 0.81, P < 0.02). Gastric pH was unaffected. CONCLUSIONS: The study hypothesis was rejected; indeed gastric emptying tended to be faster for the unmodified than the dephosphorylated protein. This effect was more pronounced in subjects with slow gastric emptying on the dephosphorylated preparation. Properties other than the size of protein precipitates determine the rate of gastric emptying for milk based formula.     

Effects of calcium channel inhibitors on ethanol effects and pharmacokinetics in healthy volunteers

Previous studies have shown that calcium channel antagonists alter the effects of alcohol in animals and humans. We selected a phenylalkylamine, verapamil, and a dihydropyridine, nimodipine, to determine whether these drugs would affect the subjective or psychomotor effects of ethanol in humans. Subjects ingested verapamil (80 mg, PO), nimodipine (30 and 60 mg, PO), or placebo 60 min before drinking an alcohol (0.7 g/kg) or placebo beverage. Subjects' mood, psychomotor performance, physiological status, and blood alcohol levels were assessed up to 3 h after beverage ingestion. Alcohol increased “drunk” ratings and impaired psychomotor performance (p < 0.05). Blood alcohol levels were decreased by nimodipine pretreatment, but not by verapamil pretreatment. Subjective and psychomotor effects of alcohol were not altered as a function of nimodipine or verapamil pretreatment. Nimodipine, verapamil, and alcohol, either alone or in combination, had no effect on blood pressure or heart rate.     

Immunomodulatory effects of a probiotic drink containing Lactobacillus casei Shirota in healthy older volunteers

Purpose

There is growing evidence that probiotics confer health benefits to the host by modulating immune function, especially in older people, where immunosenescence is a feature even of healthy ageing. The aim of this study was to investigate the effect of a probiotic drink containing Lactobacillus casei Shirota (LcS) on immune function in a healthy non-immunocompromised older population.

Methods

Thirty healthy old volunteers were recruited into a randomized placebo-controlled, single-blind crossover study. The volunteers were supplemented with the probiotic drink containing 1.3 × 10¹⁰ CFU LcS or skimmed milk per day for 4 weeks, followed by 4 weeks of washout and were crossed over to the other treatment. Peripheral blood and saliva samples were collected at baseline and end of each treatment.

Results

Probiotic consumption was associated with a significant increase in natural killer (NK) cell activity relative to baseline and a significant decrease in the mean fluorescence intensity of CD25 expression in the resting T cells compared with placebo. Additionally, there was a trend towards an increased ratio of IL-10 to IL-12 relative to baseline after LcS intake.

Conclusions

Consumption of a probiotic drink containing LcS improved NK cell activity and tended to produce a more anti-inflammatory cytokine profile in an older population.     

Acute effects of lyophilised red wine on total antioxidant capacity in healthy volunteers

This is an open, cross-over study to examine the acute effects of lyophilised red wine (LYOW) on total antioxidant capacity and some metabolic variables in 10 healthy subjects (age 27.7 +/- 3.9 yr) following a light meal. Each subject was studied on two occasions for a 360-min period, after consumption of a 1.22 MJ (291 kcal) meal; on one occasion without and on another occasion with intake of LYOW with high antioxidant activity [15.4 mM trolox equivalent (eq)]. Plasma oxygen radical absorbance capacity (ORAC) values decreased significantly after meal alone from 4.97 +/- 0.499 to 4.39 +/- 0.383 mM trolox eq. (mean +/- SD; p < 0.05) and remained lower until 360 min compared to basal values (p < 0.05). In contrast, ORAC values after meal with LYOW increased significantly from a baseline of 4.79 +/- 0.356 to the highest value of 6.39 +/- 0.570 mM trolox eq at 90 min; then, it decreased to a plateau of 4.99 +/- 0.316 mM trolox eq (p < 0.05), whose values were still higher than baseline ones until 360 min and also significantly different from the values obtained without LYOW from 90 to 360 min (p < 0.05). No correlations were observed between dietary antioxidant vitamin, fruit and vegetable intakes and plasma antioxidant capacity. No differences were found in plasma insulin and glucose values after meal between the two occasions. We conclude that moderate drinking of red wine (350 ml) with high antioxidant capacity increased and sustained for 360 min plasma antioxidant level of 10 healthy subjects after a meal.     

The effect of submicron fat droplets in a drink on satiety,food intake,and cholecystokinin in healthy volunteers

Purpose

Small fat droplets infused into the gut reduce food intake and hunger more than bigger ones, at levels as low as 6 g, and these effects are hypothesized to occur via satiety hormones such as cholecystokinin. It is, however, unknown whether the effect of droplet size would persist after oral consumption. It is also unknown whether an even smaller droplet size can affect hunger and food intake and at what minimum amount of fat. Therefore, the aim of the study was to test the effect of very fine fat droplets on satiety and food intake in two different quantities.

Methods

In a balanced-order 4-way crossover design, 24 volunteers consumed a fat-free meal replacement drink with either 5 or 9 g oil (rapeseed) and either 3 or 0.1 μm droplet size. Appetite scores and plasma cholecystokinin levels (in n = 12 subset) were measured for 180 min, when food intake was assessed during an ad libitum meal. Data were analyzed by ANCOVA, followed by Dunnett’s test and paired t test. The behavior of the emulsions was also characterized in a simulated gastrointestinal model.

Results

Despite faster in vitro lipolysis of the smallest droplets, neither droplet size nor fat amount affected satiety or food intake. From t = 45–150 min, cholecystokinin response was 50 % higher (P < 0.05) after the 0.1 versus 3 μm, but only with 9 g fat.

Conclusion

When this particular fat at these amounts is delivered in a meal replacement drink, droplet size does not influence appetite or food intake. This effect is independent of the amount of fat or plasma cholecystokinin changes.     

Fish oil supplementation modulates immune function in healthy infants

(n-3) PUFA influence immune function in adults and may also affect immune maturation during development. This randomized trial is, to our knowledge, the first to investigate whether fish oil supplementation in late infancy modifies immune responses. The study was a 2 x 2 intervention in 64 healthy Danish infants, who received cow's milk or infant formula alone or with fish oil (FO) (3.4 +/- 1.1 mL/d) from 9 to 12 mo of age. Before and after the intervention, fatty acid composition of erythrocyte membranes, plasma IgE, C-reactive protein, and soluble IL-2 receptor concentrations were measured. TNF-alpha, INF-gamma, and IL-10 concentrations in whole-blood cultures, stimulated for 22 h with LPS+phytohemaglutinin (PHA) or Lactobacillus paracasei, were also determined. IgA was measured in feces when infants were 10 mo of age. FO supplementation effectively raised erythrocyte (n-3) PUFA (P < 0.001), increased L. paracasei-induced INF-gamma (P = 0.05) and tended to reduce LPS+PHA-induced IL-10 (P = 0.08). The FO intervention did not affect any of the other analyzed immune variables. The erythrocyte content of eicosapentanoic acid was negatively associated with LPS+PHA-induced IL-10 (r = -0.38, P = 0.02). Feeding milk rather than formula did not affect cytokine production, but plasma soluble IL-2 receptor concentration was greater in the formula group than in the cow's milk group (P = 0.03). Since the capacity to produce INF-gamma has been proposed as a maturation marker for the immune system in early life, this study suggests a faster immune maturation with FO supplementation with no apparent reduction in immune activation. The implications for later health need further investigation.     

Soy isoflavones modulate immune function in healthy postmenopausal women

BACKGROUND: The immune system may be compromised after menopause because of the effects of aging and diminishing concentrations of estrogen, an immune-modulating hormone. Isoflavones, plant-derived compounds with estrogenic and antioxidant properties, may offer immunologic benefits to women during this stage of life. OBJECTIVE: The objective of this study was to evaluate the effects of soy isoflavones, both in soymilk and in supplement form, on markers of immunity and oxidative stress in postmenopausal women. DESIGN: Postmenopausal women aged 50-65 y (n = 52) enrolled in this 16-wk double-blind, placebo-controlled trial were randomly assigned to 1 of 3 experimental groups: 1) control, 706 mL cow milk/d plus a placebo supplement; 2) soymilk, 71.6 mg isoflavones derived from 706 mL soymilk/d plus a placebo supplement; and 3) supplement, 70 mg isoflavones in a supplement plus 706 mL cow milk/d. Plasma and 24-h urine samples were obtained at baseline and at 16 wk. Immune variables included lymphocyte subsets, cytokine production, and markers of inflammation and oxidative damage. RESULTS: Isoflavone intervention in postmenopausal women resulted in higher (P < 0.05) B cell populations and lower (P < 0.05) plasma concentrations of 8-hydroxy-2-deoxy-guanosine, an oxidative marker of DNA damage. Isoflavone treatment did not significantly influence concentrations of interferon gamma, interleukin 2, tumor necrosis factor alpha, or C-reactive protein in plasma or of 8-isoprostane in urine. CONCLUSIONS: Soymilk and supplemental isoflavones modulate B cell populations and appear to be protective against DNA damage in postmenopausal women.