Kidney Nutrition: Understanding types of sugar and PKD
Sugar is a type of carbohydrate. It comes in many different forms such as glucose, fructose, galactose, sucrose, maltose and lactose. These are called monosaccharides and disaccharides and are often found in different foods. For example:
- Glucose is often found in the blood
- Fructose is found in fruit and is one of the sweetest naturally occurring sugars
- Galactose is a natural sugar that is often combined with other sugars to make disaccharides like lactose
- Sucrose is made up of fructose and glucose is also known as table sugar
- Maltose is two glucose molecules often found in beer
- Lactose is a disaccharide made of glucose and galactose and found in milk-based products
There are different definitions of sugar in food according to the World Health Organization, so let’s explore them:
- Total sugars: includes natural sugars in fruit, vegetables, milk sugar, and sugar added to foods and beverages
- Free sugars: include sugars added to foods and beverages, and cooked or consumed sugars such as honey or fruit juices
- Added sugars: includes sugars added during food processing
Sugar gives us energy because it has calories. However, some natural sugars from fruits, vegetables, and dairy products (such as milk or yogurt) also have other essential nutrients like fibre, protein, vitamins, and minerals that we need in our diet.
Free or added sugar comes in many forms including white sugar, brown sugar, molasses, honey, maple syrup, and corn sweeteners such as high-fructose corn syrup. Free sugar and sugar added to food have no additional nutritional value, and can lead to a rise in blood sugar, especially in those with diabetes. Some of the most common sources of free or added sugars include sweetened beverages (e.g. pop, juice, sports drinks, hot chocolate, specialty coffees), baked goods, candies, and chocolate.
While our bodies are unable to differentiate natural, free, and added sugars when we metabolize them, free and added sugars tend to be digested more quickly because they are not associated with fibre or protein in foods.
It is estimated that Canadians eat about 110 g of sugar per day. This is 26 teaspoons. This includes sugar from all sources including milk products, vegetables, and fruit, as well as free sugars. Let’s look at what this may mean for health.
Risks of consuming too much sugar
Excessive intake of free or added sugars provides extra calories with little nutrient benefit which can lead to unhealthy weight gain, dental caries, and are associated with conditions such as those below.
Lifestyle management is important to manage PKD, and this includes reducing free and added sugars. Unlike chronic kidney disease (CKD), PKD is not caused by uncontrolled blood sugars. However, those with PKD and diabetes have been shown to have larger kidneys and earlier hypertension onset.
Newer studies in animal models are showing that cysts may use sugars as an energy source suggesting that reducing free and added sugars may be helpful to disease progression. However more studies in humans are needed.
At this time, being aware of free and added sugar sources including sugar-sweetened beverages can help to improve blood sugars, especially those with diabetes and is important for overall health.
And this month is National Diabetes Awareness Month so what better way than to discuss simple changes we can make to improve blood sugars. If you do not have diabetes, reducing your free and added sugars can be a healthy lifestyle change overall with PKD.
Gout or high uric acids in the blood has been associated with many kidney conditions, commonly including PKD. From a nutrition perspective, added sugars – and specifically sugar sweetened beverages like those weight high-fructose corn syrup – can increase waste products that lead to higher levels of uric acid in the blood, which can cause gout symptoms (in addition to large portions of animal protein). Making nutrition changes can help to prevent gout flares.
Excessive amounts of free and added sugars from sucrose and high-fructose corn syrup have been shown to increase cholesterol levels, specifically triglyceride values. Cardiovascular health is important with PKD. As a result, reducing free and added sugar sources can help to improve heart health. Try choosing fruit instead of juice, and look for strategies to reduce sugar in baked goods. In fact, you can reduce the sugar recipe by 25-33% without a change in the final product. Plus reading food labels is a great way to see how much sugar you are consuming.
How much sugar should we eat? – reading labels, other names for sugar
Current recommendations are to consume no more than 10% of total calories per day from added sugars, and ideally less than 5%. For an individual on an average 2,000 calorie-a-day diet, 5% of calories is about 28 grams (or 6 teaspoons) of added sugars.
To put that into perspective, let’s take a look at some examples:
- One can of pop contains about 39 g sugar, or approximately 10 teaspoons of daily added sugar
- Two chocolate chip cookies have 9 g sugar, or approximately 4.5 teaspoons of daily added sugar
What should I eat?
Foods that naturally contain sugar such as vegetables, fruit and milk should be included in a healthy diet in reasonable quantities. Managing your weight, healthy eating habits, and being active can help you manage your blood sugars with PKD. Here are some tips for managing your sugar intake:
1. Don’t drink your calories. Choose water as your beverage of choice. Add flavoring like strawberries or lemon to change up the taste. Or try this Sparkling Tea recipe for staying hydrated:
This carbonated tea is a great twist for your usual beverage routine. It can be made with decaf or caffeinated tea, but some of the best flavours include black tea, green tea, white tea, or herbal tea like mint or blueberry. In fact, steeping in cold water helps to increase the sweetness naturally, so you don’t need to add any extra sugars.
1 tea bag or 1 teaspoon of loose-leaf tea
2 cup sparkling water
Additional toppings: mint leaves, lemon wedge
1. Pour sparkling water into a mason jar or water bottle, add tea.
2. Let infuse for at least 12 hours.
3. Add additional toppings before enjoying.
2. Include whole foods. Enjoy a piece of fruit like a clementine or apple instead of juices. This helps to provide you with vitamins and fibre in addition to quenching your thirst.
3. Look for lower-sugar foods. Read food labels and choose foods with 5% Daily Value or less for sugar. Check the ingredient list for sources of sugar.
Written by: Emily Campbell, RD CDE MScFN is a Registered Dietitian and Certified Diabetes Educator with a Master’s Degree in Foods and Nutrition. Emily specializes in renal nutrition helping those with kidney disease overcome the confusing world of nutrition to promote health. Emily can be found at kidneynutrition.ca.