Everything Explained Carbohydrates
Everything Explained – Carbohydrates
Katie Williams M.Sc. (Dist) R Nutr
Celebrity diets usually feature ‘carbs’ in some way whether it’s no carbs, low carbs or no carbs after 5pm. Combined with the fact that there are different types of carbohydrates which are often given different names, it’s no wonder that a lot of confusion surrounds carbohydrates both in human and equine nutrition.
Back to Basics
There are three distinct groups of carbohydrates, which are:
- Simple sugars eg glucose, fructose
- Storage sugars eg starch, fructan
- Structural polysaccharides or “fibre” eg cellulose
Simple Sugars
Simple sugars are also referred to as water soluble carbohydrates as they are soluble in water or gut fluids. The most common sugar in plants is sucrose, which is a double sugar (disaccharide) consisting of glucose and fructose. Sugar is often reported to be bad for horses and molasses, in particular, comes in for a lot of criticism. To put this into context, grass contains between 1% and 5% as fed which would mean that a horse would only have to eat 8kgs of grass to consume the same amount of sugar as 1kg of pure molasses would supply. As molasses only tends to be added in relatively small quantities to feeds, it provides low levels of sugar compared to other sources.
A lot of the sugar is lost from grass when it is made into hay but soaking hay prior to feeding can remove even more sugar and so is advisable for horses and ponies requiring a low sugar diet, such as those prone to laminitis.
Storage Sugars
The plant makes sugar to use as its own energy source for growth. When it has more sugar than it needs it stores the surplus; grasses in temperate regions store sugar as fructan in its leaves and stems and as starch in seeds. If paddocks are grazed regularly the grass rarely gets the opportunity to go to seed and so starch levels in grass are usually relatively low.
Fructan tends to accumulate in grass when the grass plant isn’t growing. As light is required for sugar production (photosynthesis) but a temperature above 5°C is needed for growth, cold bright mornings can result in high levels of fructan accumulating.
Cereal grains such as barley and wheat are the seed of the cereal plant and so contain very high levels of starch. Just as you and I wouldn’t eat raw potatoes or pasta because they wouldn’t be very digestible, cereals fed to the horse can be cooked to improve their digestibility and reduce the risk of digestive upsets.
Structural Carbohydrates
The final group of carbohydrates is fibre which can also be referred to as structural carbohydrates. Cellulose is the most abundant carbohydrate in the world making up between 20% and 40% of the dry matter of plants. Cellulose, like starch, is made up of glucose molecules but it is the bonds linking the glucose together that differ and so create two very different carbohydrates.
Cellulose is joined in a way that means enzymes produced by mammals, including both humans and horses, are unable to break down the bonds. Herbivores rely on the population of bacteria present in their digestive systems to break down the bonds and release the energy from the fibre. The lack of fibre digesting bacteria in our digestive systems means that we can’t use fibre as an energy source.
Feeding Carbohydrates to Horses
Fibre should form the basis to all horses’ rations. As it is a complex structure it takes the bacteria a long time to break it down and so fibre provides slow release energy. Relative to this, starch provides quick release energy for horses but for humans it is the slowest source of energy as we can’t access energy from fibre. This is why porridge oats for breakfast should keep you feeling full for longer and yet oats can act like rocket fuel for some horses!
If you would like further information then please do not hesitate to contact the Dengie Feedline on 0845 345 5115.
