© Springer International Publishing Switzerland 2015David A. Schulsinger (ed.)Kidney Stone Disease10.1007/978-3-319-12105-5_28
28. Diet Fads and Stones: Is Your Diet All Cracked Up to What It Is Supposed to Be?
Department of Urology, Stony Brook Medicine, Stony Brook, NY, USA
Department of Clinical Nutrition Services, University of Wisconsin Hospital and Clinics, Madison, WI, USA
Summary of Dietary Facts
Not all diet plans are the same.
Some dietary patterns are lithogenic and favor stone formation, while others do not.
In diets that are rich in protein and low in carbohydrates, there is a greater risk to form both uric acid and calcium oxalate stones.
If on a weight loss diet, be aware that you may be forming stones, depending on the diet.
You are ready to begin your new diet. Your desire is to lose weight or to initiate a diet for other health-related reasons. You may have been recently diagnosed with diabetes, hypertension, hyperlipidemia or coronary artery disease and your physician suggested dietary modification as an initial therapy. You may also have stress incontinence and your physician suggested that it would be ideal to lose weight. Whichever the reason, you were recommended a new diet plan. Are you aware of the risks of this diet? As you would talk with your physician about a newly prescribed medication or an anticipated surgical treatment, you want to know what the risks and benefits of these treatment options. Likewise, you should know what the risks and benefits are of your new diet. Would you be surprised to know that your weight reduction diet might also increase your risk for kidney stones?
Some dietary patterns can be stone promoting, referred to as lithogenic. Other diets may not be related to kidney stones, or they may even help to reduce your risk of stone disease. This chapter will discuss some of the more popular diets, both past and present, and their relationship to nephrolithiasis. The objective of this chapter is not to provide you with a “how to” for implementing each diet but to alert you to any risk for kidney stones that are associated with the diet. If you are planning to initiate any of these or other dietary regimens, a registered dietitian can help you identify which one would be most appropriate for your needs and what type of information you will need in order to implement the right diet plan for you.
Diets with Lower Risk of Stone Disease
Dash Diet: An Apple a Day Can Keep the Urologist Away!
The Dietary Approaches to Stop Hypertension, or DASH diet, is recommended to help patients maintain normal blood pressure. In addition to controlling hypertension, the DASH diet is recommended for patients with diabetes mellitus and other chronic diseases because of its many favorable effects. The DASH diet emphasizes a high intake, approaching or exceeding eight servings per day, of fruits and vegetables. It also particularly includes legumes, nuts, and foods made with whole grains. It includes low-fat dairy and a moderate amount of fish, meat, and poultry. The DASH diet is overall low for fat (especially saturated fat), salt, sugar, and refined grains.
One study compared recurrent calcium stone formers and stone formers with hyperoxaluria on either a low oxalate diet, a frequently prescribed recommendation for calcium oxalate kidney stone prevention and treatment, or the DASH diet. The DASH diet was modified for the study to minimize the use of nuts, which contain more oxalate than many other foods. Study results suggested that the DASH diet might be more effective than a diet restricted for oxalate at reducing urinary risk factors for calcium oxalate kidney stone formation . The DASH diet may therefore be a novel approach to prevent kidney stones and a superior alternative to the traditional recommendation to restrict dietary oxalate. Other studies have shown that the DASH diet reduces the risk of stones by 40–45 %.
While the DASH diet in the study was modified by restricting nuts, which are a regular component of the DASH diet, nuts could be consumed concomitantly with calcium containing foods, such as milk or yogurt, to maintain suitably lower risk of stones.
In summary, as hypertension and stone disease are more common in patients over the age of 40, the DASH diet may be a good approach to managing both high blood pressure and the risk of kidney stone development.
The Mediterranean diet is similar to the DASH diet. It features foods frequently consumed in Greece, Spain, Southern Italy and France, and other countries that border the Mediterranean Sea. This dietary pattern advocates foods such as fish, fruits, vegetables, legumes, whole grains, nuts, and olive oil. A moderate amount of low-fat dairy, particularly yogurt, is encouraged in this plan. Foods such as meat, cheese, and sweets are very limited. The Mediterranean diet is rich in monounsaturated fats, fiber, and omega-3 fatty acids, and encourages eating plenty of fruits, vegetables, and high-fiber grains. The Mediterranean diet, unlike other heart-healthy diets (which recommend less than 35 % of your calories from fat), recommends an average of 35–40 % of calories originating from fat. The fats encouraged in the Mediterranean diet are mainly from unsaturated sources such as fish and fish oils, olive oil, certain nuts (such as walnuts, hazelnuts, and almonds) and the oils of nuts and seeds (such as canola, soybean, or flaxseed) and from nuts.
A Mediterranean-style dietary pattern may especially protect individuals with high BMI against the risk of nephrolithiasis .
Weight Watchers Diet
Consistently ranked the #1 best plan for weight loss (by U.S. News and World Report), the Weight Watchers dietary plan is essentially a balanced diet. It can be manipulated to promote weight loss by reducing portion sizes to reduce calorie intake, especially limiting foods highest in energy (calorie) density. While the weight loss success of the plan may have as much or more to do with the group support it provides, its “point” system framework is associated with ease of use and acceptance. There are virtually no foods that are restricted, but emphasis is placed on those lowest in fat. Dairy consumption is allowed. Fruits and vegetables of all types are encouraged. The Weight Watchers diet can be made to be consistent with vegetarianism. The Weight Watchers diet can also be inappropriately followed, if adherents were to over-emphasize certain foods to the exclusion of others even while remaining within the points system.
Neither the Weight Watchers diet nor weight loss per se has been studied with respect to kidney stone risk. But both would theoretically be associated with low lithogenic risk factors if followed appropriately in a balanced way.
Vegetarian diets span the gamut from vegan – which is the absence of any animal- or insect-derived foods and food products – to those that include dairy, eggs, and/or fish. People following vegan diets avoid honey and any food dyes or additives that are animal or insect-derived. Some ethnic diets, such as Asian and Mexican, are largely plant-based and thus may be considered vegetarian diets, depending on the individual. Surveys have shown that the risk for stone disease is 40–60 % lower in persons consuming vegetarian diets. People consuming vegetarian diets compared to omnivorous diets, particularly the Western style, have a decreased risk of uric acid crystallization . Vegetarian diets can provide an excellent supply of whole grains that are high in phytic acid, a plant constituent associated with a 40 % reduced risk of calcium stone formation in individuals eating higher compared to lower levels . It is important to note, however, that vegetarian diets can be just as unhealthy as non-vegetarian diets. Just because a person is “vegetarian” does not necessarily mean that he/she consumes adequate fruits and vegetables or eats a suitably low amount of saturated fat. Even the intake of whole grains can be suboptimal in a vegetarian diet if a preponderance of foods that are more ample for refined grains are consumed instead.