Monday, April 2, 2012

Does Vitamin B12 level Affect Stress Urinary Incontinence?


It is a fascinating question because very little is known about how diet affects Stress Urinary Incontinence. Most doctors will counsel patients about diet adjustment when urge incontinence is the issue, such as lowering caffeine or other stimulants in your diet to lower the irritability of the bladder, or avoiding spicy or acidic foods if there is a question of Painful Bladder Syndrome (sometimes called Interstitial Cystitis). But not much is said in regards to dietary influences on Stress Urinary Incontinence. Conservative measures to help SUI include fluid restriction and Kegels. When this fails, and if SUI is bothersome enough, sling surgery is the most successful surgical intervention.

The risk factors for SUI are well known and include vaginal childbirth, age, repetitive straining (constipation, chronic cough, heavy jumping exercises), as well as menopause and hysterectomy. We also know that there are connective tissue differences in collagen between women who have urinary incontinence and vaginal prolapse and those who don’t. Studies over the last 10 years have slowly mapped out certain enzymes and proteins that degrade and turnover collagen more readily in the pelvic floor of women with urinary incontinence and prolapse. This lends weight to the notion that these bladder conditions are genetic and run in families. It’s often true that my patients who have urinary incontinence and/or prolapse will say that their mother, grandmother, or aunt also had “these problems” as well.

Recently, a study from Istanbul addressed the question as to whether there are dietary influences on SUI. Vitamin B12 was selected for study because of its integral role in connective tissue production of collagen. Since collagen is the main connective tissue in the body (and there are several forms of it), the researchers wanted to see, quite simply, if there was a correlate between Vitamin B12 levels and symptoms of stress incontinence. More simply, is Vitamin B12 deficiency seen in women with stress incontinence, whereas is it normal in those without SUI?

 This is a huge connection if one exists. Why? One assumption is, if B12 is lacking does this outright lead to stress incontinence? If this is true, does B12 replenishment correct SUI, or prevent/lessen SUI in the face of other risk factors? Can SUI be completely prevented by keeping B12 levels high? (Likely not given all the other potential life cycle risk factors).  Perhaps the connection is not as direct. Perhaps in some women there is a genetic predisposition to not absorbing B12 well in the gut, and this is the weak link which may predispose to SUI. Perhaps diet preferences based on fads or religious beliefs lead to less B12 intake. Moreover, there are many factors which affect collagen synthesis and degradation, not just B12 levels, yet this question has never been raised.

The researchers looked at 2 groups of women, both about 50 years old; the study group had stress urinary incontinence and the control group did not. B12 levels were then drawn from both groups. (How simple!) Under 200 pg/mL is considered deficient, while 200-350 is considered low-normal. The threshold for 300 pg/mL was used as the cut off, mimicking other prior B12 studies.

In the study group, the B12 level was 300.95 vs. the control group which had a B12 level of 598, a significant difference. When comparing the two groups, other characteristics such as BMI, folic acid level, and employment status were no different. In the study group of women with SUI, the mean number of years they had it was 7.4 yrs. In fact, women with B12 levels less than 200 pg/mL had SUI for longer. The prevalence of B12 deficiency was seen to be 66%, a rate higher than the general population.

In analyzing their data, the researchers refer to a prior study that suggested that zinc and B12 may be associated with SUI. These micronutrients are acquired in meat and dairy products. If women perceive “being healthy” by avoiding meat and dairy, are they really doing themselves a disservice? If proper nutrition calls for a balanced diet, then are “salad eaters” who work out in the gym to maintain weight control doing so at the expense of true health…? This is a larger question that cannot be addressed in this blog, however it does give one pause to consider the need for a balanced diet. Of course B12 shots can always be used to supplement low levels, yet that steals the satisfaction from the individual from enjoying some good foods.

The researchers of this current study did suggest that B12 deficiency may be a causative factor in developing stress urinary incontinence. Among the study group women, almost all were still premenopausal and so the “protective effect” of estrogen was still present. Diet is the main source of B12 and a poor diet may have contributed to SUI, over time. Middle age women, not young women were the ones demonstrating SUI, yet in this older age group other SUI risk factors may have also played a role such as birth history and age.  It is too big a leap to directly suggest that simply lack of B12 lead directly to SUI, but B12 is a critical nutrient that is required to maintain good overall health, not just of the connective tissue system, but is also needed for good bone marrow support and bone health. Low B12 leads to anemia and bone loss as well.

B12 may be considered a useful biomarker for poor overall nutrition in middle aged women, but only some doctors check it on routine exam. So, perhaps, if you have SUI, check your B12 level. It may help your overall health as well.