Carbohydrates and their Relationship with Water

When we think of carbohydrates, we tend to think of energy, given that carbs are a primary fuel source for our bodies. However, carbohydrates have a complex relationship with water that extends their role beyond merely providing us with energy. Different types of carbohydrate molecules interact with water in unique ways, resulting in diverse metabolic effects, and contributing to overall homeostasis and well-being. Let’s explore these interactions and what they mean for our bodies.

Simple Sugars: Table Sugar’s Water Affinity

Take sucrose, or table sugar, as an example. Sucrose is a disaccharide made of glucose and fructose. When you dissolve it in water, the sugar initially saturates water within its molecular structure. This means that the water molecules surround and engage with the sugar molecules in a way that is almost like a ‘pre-dissolution’ state. If enough water is present, the sugar disperses entirely, dissolving into individual molecules that are spread evenly throughout the liquid. This is what happens when you put sugar in your coffee, for instance.

Starch: A Different Mode of Dispersion

Starch, on the other hand, interacts with water differently. Starch is a polysaccharide, a type of molecule that is made up of multiple glucose units. Starch is primarily found in foods like potatoes and grains. When starch meets water, it does not dissolve in the same way sugar does. Instead, the water molecules penetrate the starch granules, causing them to swell. This leads to a semi-dissolved, gel-like substance, and explains why starch is often used as a thickening agent in foods.

Soluble Polysaccharides: Pectin and Beta-Glucans

Then we have the soluble, viscous polysaccharides like pectin and beta-glucans, which interact with water in yet another distinct way. These carbohydrates are also hydrophilic, meaning that they attract water, but they do not disperse into water. Rather, they attract and bind water into their structures, forming a gel-like substance.

Unlike sucrose and starch, which primarily serve as sources of energy, soluble polysaccharides are not readily metabolized for energy as they can not be broken down by digestive enzymes.

However, they do have numerous metabolic effects. For example, they can influence the balance and homeostasis of hormones. And although they cannot be digested and used for energy as is the case for glucose, they can be broken down by fermentation into short-chain fatty acids like acetate, propionate, and butyrate. These short-chain fatty acids serve as energy sources for the cells that line the gut, helping maintain the health and integrity of the intestinal lining. In this way, they contribute to gastrointestinal health, which in turn has a positive impact on many systems in the body, including the brain via the gut-brain axis.

The Metabolic Implications

The way that sucrose and starch relate with water has implications for digestion and absorption rates, potentially leading to blood glucose spikes which impact the insulin response. On the other hand, soluble polysaccharides like pectin and beta-glucans have a more nuanced role. They may not be energy sources themselves, but their unique, gel-forming interactions with water have wide-reaching effects, including potential benefits for conditions like high cholesterol, diabetes, and even certain types of cancer. We will discuss these benefits more closely in an article focusing on beta-glucans.

Rethinking Carbohydrates

The common thread that ties these carbohydrate forms together is their relationship with water. Whether it’s the simple dissolving action of table sugar, the thickening properties of starch, or the water-attracting abilities of pectin and beta-glucans, the way these molecules interact with water has significant metabolic and physiological implications.

By shifting the focus from merely viewing carbohydrates as energy providers to understanding their complex interactions with water, we can better appreciate their varied roles in health and disease. 

Hi! I’m Hilary Jacobson, and I’ve been helping moms tackle milk supply issues for over 30 years. My book, ‘Mother Food,’ was a game-changer when it first came out, and I’m still at it—researching, writing, and teaching to make sure new moms get the support they need. Want to stay in the loop? Sign up to my newsletter for updates. 

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