The Mediterranean Diet and Kidney Disease
Once chronic kidney disease develops, in most cases the condition is progressive eventually resulting in end-stage kidney disease that requires dialysis or a transplant. Dialysis and transplantation, though life-saving, are not without serious life-threatening complications including weakening of bones, infections, heart attack, stroke, and premature death. An exhaustive amount of research has been conducted on how to slow down the progression of chronic kidney disease.
While many types of interventions have been recommended to help prevent kidney disease and stop the progression of chronic kidney disease, one which has been widely studied is Diet. There is ample evidence indicating that a non-meat diet or a vegetarian diet may be beneficial for the prevention of kidney disease and slowing down the progression of chronic kidney disease. One diet in particular that has credible evidence for kidney protection is the Mediterranean diet.
What is the Mediterranean diet?
In the 1960s it was observed that people living around the Mediterranean had fewer deaths from heart disease and stroke compared to Northern Europeans and North Americans. In countries like Greece, Italy, Portugal, and Spain not only was coronary artery disease less but these people also had markedly lower blood pressure and decreased rates of diabetes. Subsequent investigations revealed that one common universal feature in these individuals was their diet- the so-called Mediterranean diet.
Since then there have been many studies on the Mediterranean Diet- all of which have shown that this diet is of benefit in preventing heart disease and stroke. Thus, today, the Mediterranean diet is recognized by the World Health Organization as a sustainable and healthy diet. For this reason, it is widely promoted globally including the United States for the prevention of stroke and heart disease.
What defines a Mediterranean diet?
There is no universal definition of what a Mediterranean diet is but typically the diet is high in fruits, vegetables, nuts, whole grains, unsaturated oil, and a variety of seeds. The key dietary components of the Mediterranean diet include the following:
- Regular consumption of fruits, vegetables, unsaturated fats, and whole grains
- Moderate intake of dairy products like cheese, yogurt, and eggs
- Weekly consumption of poultry, fish, and legumes like beans (to increase fiber content)
- Low intake of red meat
Besides the foods, the other key feature of the Mediterranean diet is the way it is consumed. In most cases, the diet is consumed in a social gathering of family and friends and the consumption of red wine is not unusual. Unlike many other diets, physical activity is not mandatory but lately, most healthcare workers recommend some type of regular exercise.
What type of fats are included in the Mediterranean diet?
Unsaturated fats are the main feature of the Mediterranean diet. Instead of consuming saturated and trans fats, the diet relies heavily on unsaturated fats like olive oil. Olive oil is rich in unsaturated fats and is known to lower the levels of cholesterol and bad cholesterol (LDL-cholesterol). Besides, the consumption of seeds and nuts also contain a healthy amount of unsaturated fat.
Another key feature of the Mediterranean diet is the consumption of fish because they are rich in omega 3 fatty acids. Types of Fish known to contain these unsaturated fatty acids include sardines, herring, mackerel, salmon, tuna, and lake trout. The omega 3 fatty acids are known to be potent antioxidants and reduce inflammation. They also reduce blood clotting, lower triglycerides, and decrease the risk of heart disease and stroke.
The Mediterranean diet also permits the consumption of red wine in moderation. Red wine has been shown to lower the risk of heart disease in some studies, but the beverage is not risk-free. Too much wine can cause liver problems and its benefits are not seen in everyone.
So how should the Mediterranean diet be consumed daily?
- Eat more veggies and fruits every day.
- If you have a choice, select whole-grain bread, pasta, and cereal
- Use olive oil as a source of unsaturated fats for cooking
- Eat seafood at least twice a week. The recommendation is to buy fresh fish and grill them. Deep-fried fish is not recommended
- Lower the consumption of red meat
- Eat low-fat dairy products, eggs, and cheese
- Use ample herbs and spices or flavor and lower the use of salt.
So what is the role of the Mediterranean diet in individuals with chronic kidney disease?
Because the Mediterranean diet has been shown to lower high blood pressure, reduce blood sugars, lower bad cholesterol, and increase the levels of good cholesterol, it is widely promoted for the prevention of heart disease and stroke. But is the Mediterranean diet of any benefit in preventing kidney disease and slowing down the progression of chronic kidney disease?
The Latest Study
Over the years, extensive data has accumulated showing that a poor diet cannot only worsen kidney disease but can cause progression to end-stage kidney disease. Several studies in the past indicated that a plant-based diet offered kidney protection and prevented progression to chronic kidney disease. But asides from the DASH diet, no other formal study on diet has been done in evaluating kidney disease. Hence, researchers looked at the role of the Mediterranean diet and its role in kidney disease
In the latest study conducted at Columbia University Medical Center in New York, researchers followed 900 patients for 7 years. Each participant was then evaluated after maintaining a diet similar to the Mediterranean diet, consisting chiefly of plant-based food, and consumptions of fish but not red meat twice a week.
The results showed that participants who adhered closely to the plant-based diet were 50% less likely to develop chronic kidney disease ad 42% were less likely to develop progression or rapid deterioration of kidney function compared to participants who did not adhere to the diet,
So what does this mean?
It is clear today that diet plays a vital role in the maintenance of kidney function. When a plant-based diet or the Mediterranean diet is selected, individuals are less likely to develop kidney disease and even if they have chronic kidney disease, the progression to end-stage kidney disease is slowed down.
While there are many health benefits of the Mediterranean diet it is important not to overeat. Nutrition experts recommend eating no more than 2,000 calories for males and 1,800 calories for females. Even though olive oil is rich in unsaturated fatty acids, it should not be used in large amounts as this will negate its health benefits. When possible, too much oil should be avoided. Instead of deep-frying foods, grilling is a better option. Any excess calories will be converted to fat.
What foods are not allowed in the Mediterranean diet?
- Individuals who have been started on a Mediterranean diet should avoid the following foods:
- Fast foods like burgers pizza, deli meats, and other processed foods
- Refined grains like white pasta, white bread, and pizza dough all contain white flour
- Foods that have a high load of sugars like cola beverages, pastries, cakes, desserts, and candies
- Refined oils such as soybean and canola oils
- Fast foods like burgers pizza, deli meats, and other processed foods
Should the individual exercise when eating the Mediterranean diet?
While the above study did not assess the role of the Mediterranean diet combined with exercise in kidney disease, in North America when the Mediterranean diet is prescribed, exercise is almost always recommended. The type of exercise is not that important, the key is to be physically active; even walking every day is as good as exercise as any other physical activity. However, walking has to be done regularly for 45 to 60 mins at least 5 times a week.
Is the Mediterranean diet alone beneficial in the prevention of chronic kidney disease?
No, people with or without kidney disease should never rely on just diet for the maintenance of good health. The individual with kidney disease who want to preserve kidney function need to do the following besides consuming the Mediterranean diet:
- Stop smoking- this is an absolute must
- Ensure good control of the blood pressure; this usually requires the use of medications and compliance is vital
- Control blood sugars: close follow up with a healthcare provider is recommended to ensure that the blood sugars are within normal with the use of medications, insulin, or exercise
- Be physically active
- Limit the intake of salt
- Follow up with a healthcare worker
- Read labels when grocery shopping
- Maintain a healthy weight
The individual with kidney disease should consult with a dietitian to know more about the Mediterranean diet and what types of recipes they can make and what they should not eat.
There is no longer any debate about the health benefits of the Mediterranean diet over the typical American diet. This plant-based diet has been shown to cause less stress on the kidneys and reduce the acid load on the different body organs. In addition, because the Mediterranean diet is rich in antioxidants, it is also known to decrease inflammation and overall mortality. However, it is also important not to solely rely on the Mediterranean diet because the kidney is a complex organ and many other factors are involved in its normal function. The blood pressure and blood sugars should be well controlled and one should stop smoking. To ensure that the kidney is functioning normally it is also important to have the blood parameters checked at least once every 6 months. Finally, follow up with a kidney doctor is essential if one wants to prevent the progression of the disease.
- Mediterranean Diet May Help Preserve Kidney Function
- Mediterranean Style Diet and Kidney Function Loss in Kidney Transplant Recipients. https://cjasn.asnjournals.org/content/15/2/238
- Mediterranean diet as the diet of choice for patients with chronic kidney disease