Milk Powder Cuts Gout Flares

By Nancy Walsh, Staff Writer, MedPage Today MedPage Direct Link
Published: January 23, 2012
Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine and Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner

4 comment(s)

Action Points

• Observational studies have shown an inverse relationship between low-fat dairy intake and the risk of developing gout. This study evaluates this observation with a randomized, controlled trial.
• Point out that this study suggested that skim milk powder enriched with two dairy fractions reduces the frequency of gout flares in patients with recurrent episodes of gout.

Daily consumption of enriched skim milk powder could help prevent gout flares, a proof-of-concept study suggested.

Compared with patients randomized to receive control treatment with simple powdered lactose, those given enriched skim milk powder had greater reductions in flares of gout during a three-month period (P=0.044), according to Nicola Dalbeth, MD, of the University of Auckland in New Zealand, and colleagues.

However, there was no difference in flare frequency for patients given plain skim milk powder rather than the enriched formulation, compared with those given lactose (P=0.81), the researchers reported online in Annals of the Rheumatic Diseases.
Longitudinal observational studies have shown an inverse relationship between low-fat dairy intake and risk of developing gout. Previous work also has suggested that increased intake of skim milk or milk protein can help lower serum urate. Moreover, the specific fractions glycomacropeptide and G600 milk fat extract, used to enrich skim milk powder, have been shown to exert anti-inflammatory effects in a murine model.
"These agents may have reduced gout flares through inhibition of the inflammatory response to monosodium urate crystals present within the joint," the researchers explained.
To assess the potential of these milk fractions for limiting flares of gout, Dalbeth and colleagues enrolled 120 patients with inadequately controlled gout.
Participants' mean age was 56, and most were white men.
Slightly more than half were taking allopurinol (Zyloprim), and during the month prior to enrollment, the average number of flares was 1.5.
At baseline, the median intake of low-fat dairy was slightly over one serving per day.
The lactose control, skim milk control, and enriched skim milk treatments all were administered as daily vanilla-flavored shakes.
Aside from decreased frequency of flares, the enriched powder was associated with "clinically relevant endpoints," such as lower pain scores compared with lactose (P=0.048), the researchers reported.
There also was a significant increase in fractional uric acid excretion for the enriched skim milk group compared with both the lactose group (P=0.0002) and the plain skim milk group (P=0.020).
For tender joint counts, a trend was seen for improvements in the enriched group (P=0.066), but no differences were found for swollen joint counts.
Adverse events were similar in the three groups, being reported by about half of all participants.
Most of the events were gastrointestinal, such as nausea or diarrhea, occurring in 13% of the lactose group, 5% of the plain skim milk powder group, and 18% of the enriched milk powder group.
Serious adverse events included hospitalization for gout flare or falls, and were considered unrelated to the study treatment.
The active treatment was not associated with any changes in lipids or serum creatinine.
A small weight gain was seen in all three groups, being about one pound in the enriched powder group.
Diastolic blood pressure fell by 3.6 mm Hg in the enriched milk powder group, which differed significantly from the lactose group (P=0.001).
The researchers termed it "noteworthy" that patients taking plain skim milk powder -- in quantities equivalent to two additional servings of low-fat dairy per day -- had no benefit, in contrast to what has been seen in previous cross-sectional studies.
Current recommendations for diet in gout call for two extra portions of dairy, based on those earlier studies, so further randomized trials should be conducted to clarify the optimal quantity, they said.
The study was limited to a single center and a population with high rates of severe gout.
An additional limitation was that the two specific milk fractions included in the enriched formulation have not be evaluated separately or in different quantities.
"Future work will be directed at determining the effects of individual fractions and various combinations," the researchers said.

The study was funded by LactoPharma and the New Zealand Government Foundation for Research Science and Technology.
The lead author and two co-authors are named on a patent application for milk products to be used in gout, and three co-authors are employees of Fonterra Cooperative Group Ltd.

Primary source: Annals of the Rheumatic Diseases
Source reference:
Dalbeth N, et al "Effects of skim milk powder enriched with glycomacropeptide and G600 milk fat extract on frequency of gout flares: a proof-of-concept randomized controlled trial" Ann Rheum Dis 2012; DOI:10.1136/annrheumdis-2011-200156.