You’ve heard it over and over again. Eat more fruits and vegetables.
Eating plenty of produce is tied to many health benefits – lower risk of stroke, cataract, macular degeneration, osteoporosis, arthritis, asthma, depression, cognitive decline and digestive tract cancers is among them.
If you have hypertension and early chronic kidney disease, consider adding at least two cups of fruits and vegetables to your daily diet.
According to a new study published this month in the American Journal of Medicine, doing so not only helps lower blood pressure, it also protects kidney and heart health.
The hypertension-chronic kidney disease link
High blood pressure, affecting almost one in four Canadians, is a leading preventable risk factor for heart disease, heart attack and stroke if uncontrolled.
It’s also a risk factor for chronic kidney disease, which involves a gradual loss of kidney function and can range from mild to severe.
Damage caused by high blood pressure impairs the ability of blood vessels in the kidneys to filter waste and excess fluids from the bloodstream.
The kidneys balance the pH level of the blood by removing acidic substances. A low blood pH level (acidic) can cause life-threatening health conditions.
About the new research
The study, a five-year randomized controlled trial, involved 153 adults, ages 18 to 70, with high blood pressure and early (stage 1) chronic kidney disease. In stage 1 chronic kidney disease, the kidneys are still filtering normally but there are signs of mild kidney damage.
The aim of the study was to test the effectiveness of reducing dietary acid on slowing the progression of chronic kidney disease and improving cardiovascular health.
Fruits and vegetables are alkaline (basic) foods, meaning they produce alkaline (base) compounds in the bloodstream after they’re digested, which increases the pH level in the bloodstream. Beans and lentils are alkaline-producing too.
The digestion of animal foods, such as meat, chicken, fish and cheese, produces acidic compounds in the bloodstream, which decreases blood pH. Grains and carbonated drinks are also acid-producing.
Participants were assigned to one of three groups: one that added two to four cups of fruits and vegetables a day to their usual diet, one that took baking soda tablets twice daily and another that continued with usual medical care. Like fruits and vegetables, baking soda is acid-reducing.
All participants were receiving standard drug therapy prescribed by their family doctor to protect cardiovascular and kidney health.
Participants in all three groups experienced a decline in blood pressure during the study, with those in the fruit and vegetable group having the largest reduction.
Those in the fruit and vegetable group and the baking soda group had a slower decline in kidney function over five years compared to participants receiving drug therapy only.
While both acid-reducing diet strategies resulted in similar kidney protection, only participants eating the additional two to four cups of fruits and vegetables a day had improvements in cardiovascular disease risk factors such as LDL cholesterol and body mass index.
The new findings are in line with results from earlier studies conducted by the researchers. In both animals and people, they showed that an acid-producing diet (high in animal foods) was harmful to kidneys while an alkaline-producing diet (high in fruit and vegetables) was healthy for kidneys.
The researchers concluded that “fruits and vegetables should be viewed as foundational” in the management of hypertension.
Related: What is the DASH diet and can it help lower blood pressure?
Ramp up your fruit and vegetable intake
High blood pressure or not, increasing your daily fruit and vegetable intake offers plenty of nutritional and health benefits. Prioritize these foods at every meal.
Include both fruit and vegetables in smoothies. Blend leafy greens, raw carrot or pumpkin puree with frozen berries, mango or pineapple, for example.
Fortify meals with greens. Stir spinach, chopped kale or Swiss chard into soups, chilis, stews and pasta sauces. Top a vegetable pizza with baby arugula before serving.
Add baby spinach, diced red pepper and sliced mushrooms to omelettes and frittatas.
Snack on fruits and vegetables instead of reaching for a granola bar or crackers.
Prep vegetables ahead. Wash and slice carrots, celery and bell pepper and refrigerate for quick meals and snacks. Grill extra vegetables to top pizzas, toss into salads or add to sandwiches.
To keep up your produce intake when short on time, stock a variety of frozen vegetables.
Serve fresh fruit for dessert to satisfy a sweet tooth.
Toss dried or fresh berries, orange segments or apple slices into leafy green salads.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD