Newswise — Drinking skim milk may help people manage their gout, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in Philadelphia, Pa.

Gout is a painful and potentially disabling form of arthritis that has been recognized since ancient times. Initial symptoms usually consist of intense episodes of painful swelling in single joints, most often in the feet (especially the big toe). Treatments are already available to prevent or control the arthritis associated with gout, but managing this disorder can be difficult, and treatment plans often have to be tailored for each person.

Previous studies have indicated that individuals who drink a lot of milk have a lower risk of developing gout. Researchers recently studied the effects of skim milk on serum uric acid concentrations, which—when at an elevated level—increase the risk of gout.

With the help of 16 healthy male volunteers, researchers studied the effects of drinking soy milk and three different types of skim milk, produced at different times of the milking season from grass-fed cows.

Each participant received a single dose of each product (each containing 80 grams of protein) in random order. Researchers collected samples of serum and urine immediately before each participant drank one of the beverages and then hourly over a three-hour period. They completed this with each participant for each of the four beverages with a week in between each session.

Researchers found that after drinking the soy milk, the serum uric acid increased by about 10 percent. In contrast, all skim milks led to a decrease in serum uric acid by approximately 10 percent. All beverages (including the soy milk) rapidly increased the ability of the kidneys to remove uric acid from the body.

Additionally, researchers found that late season skim milk led to a greater increase in the removal of uric acid by the kidneys when compared to the other skim milks. Late season skim milk is primarily available from countries where milking is seasonal and cows are grass-fed, such as New Zealand and Australia, and is known to contain higher levels of orotic acid, a substance that promotes uric acid removal by the kidneys.

Ultimately, the study showed that skim milk has a specific uric acid-lowering effect, and it might be a good dietary way to assist in the prevention and treatment of gout.

“This study has shown that skim milk can significantly reduce the serum uric acid concentration in the short term,” explains Nicola Dalbeth, MD, FRACP; senior lecturer, clinical medicine, University of Auckland, Auckland, New Zealand, and lead investigator in the study. “The results suggest that increasing the amount of skim milk in the diet may help with preventing the development of gout, and also assist with treatment for those with the disease. We are now continuing this work by studying the longer term effects of milk in people with gout.”

The ACR is an organization of and for physicians, health professionals, and scientists that advances rheumatology through programs of education, research, advocacy and practice support that foster excellence in the care of people with or at risk for arthritis and rheumatic and musculoskeletal diseases. For more information on the ACR’s annual meeting, see www.rheumatology.org/annual.

Editor’s Notes: Dr. Dalbeth will present this research during the ACR Annual Scientific Meeting at the Pennsylvania Convention Center at 4:45 PM on Tuesday, October 20 in the Auditorium. Dr. Dalbeth will be available for media questions and briefing at 1:30 PM on Monday, October 19 in the on-site press conference room, 109 A.

Presentation Number: 1947

The Acute Effect of Skim Milk On Serum Urate Concentrations: A Randomized Controlled Cross-Over Trial

Nicola Dalbeth, FRACP , Department of Medicine, University of Auckland, Auckland, New Zealand Sumwai Wong, Department of Medicine, University of Auckland, Auckland, New Zealand Greg Gamble, Department of Medicine, University of Auckland, Auckland, New Zealand Anne Horne, Department of Medicine, University of Auckland, Auckland, New Zealand Barbara Mason, Department of Medicine, University of Auckland, Auckland, New Zealand Lynette Fairbanks, Guy's Hospital, London, United Kingdom Fiona M. McQueen, Department of Medicine, University of Auckland, Auckland, New Zealand Jillian Cornish, Department of Medicine, University of Auckland, Auckland, New Zealand Ian R. Reid, University of Auckland, Auckland, New Zealand Kate Palmano, Fonterra Research Centre, Palmerston North, New Zealand

Purpose: Recent observational studies have highlighted the beneficial role of skim milk in prevention of gout. The aims of this study were to determine the acute effects of intact skim milk on serum urate concentrations, and to examine the mechanisms of the urate-lowering effects of skim milk.

Method: This was a short-term randomized controlled cross-over trial of skim milk in 16 healthy male volunteers. The following products were tested (each 80g protein); soy control, early season skim milk, late season skim milk (containing high concentrations of orotic acid, a naturally occurring uricosuric agent), and MPC 85 skim milk (an ultra-filtrated skim milk containing very low concentrations of orotic acid, purines and lactose). Each participant received a single dose of each product in random order. Serum and urine were obtained immediately before ingestion and then hourly over a three hour period after ingestion of each study product. Each study visit was separated by at least a week.

Results: Ingestion of the control soy led to an increase in serum urate by approximately 10%. In contrast, all skim milks led to a decrease in serum urate by approximately 10% (p<0.0001) (Figure). All products (including soy) rapidly increased the fractional excretion of uric acid (FEUA). Late season skim milk led to a greater increase in FEUA compared with MPC 85 (p=0.02) and early season skim milk (p=0.052). There were no significant differences over time or between groups in changes in serum oxypurines (xanthine and hypoxanthine) or purine-containing nucleosides (guanosine and inosine). However, all products led to an increased fractional excretion of xanthine (p=0.004).

Conclusion: This study has demonstrated that intact skim milk has a specific acute urate-lowering effect. These data provide further rationale for long term intervention studies to determine whether such dietary interventions play an adjunctive role in management of hyperuricaemia and gout.

Figure: Effects of soy and skim milks on changes in serum urate concentration. Data are presented as mean (95% CI). (View press release with full abstract at www.rheumatology.org).

Disclosure: N. Dalbeth, Fonterra Research Centre, 2, Abbott Laboratories, 5, Roche Pharmaceuticals, 5 ; S. Wong, None; G. Gamble, None; A. Horne, None; B. Mason, None; L. Fairbanks, None; F. M. McQueen, None; J. Cornish, Fonterra Ltd, 2 ; I. R. Reid, Fonterra Ltd, 2 ; K. Palmano, Fonterra Ltd, 3