Whether cats need carbohydrates and their value is a highly debatable issue amount nutritionists and veterinarians. Carbs have been labeled as poisons and said to cause obesity, diabetes mellitus, food allergies, and other problems. Is this just negative publicity or reality?
What are carbohydrates?
Carbohydrates are one of the three food classes used as food, the others being protein and fats. They are divided into monosaccharides (glucose, galactose, and fructose) made of a single sugar molecule that the body can directly absorb, disaccharides (lactose, sucrose, maltose, and at times trehalose) that have two sugar molecules which are easily digested, oligosaccharide and polysaccharides.
Oligosaccharides have 3-9 sugar molecules; mammals cannot digest it but are fermentable by gut microbes inside the colon, while polysaccharides are complex carbohydrates with 10+ sugar molecules, and they are divided into dietary fibers and starches.
Starches are the most abundant polysaccharides in which plants store energy, just like animals store energy as glycogen, especially in the skeletal and liver. They are liked by a beta glycosidic bond, making them digestible by α-amylase.
On the other hand, dietary fibers are indigestible polysaccharides divided into soluble (dissolves in water) and insoluble fiber (doesn’t dissolve in water), fermentable and non-fermentable, and they include pectins, cellulose, hemicellulose, gums, mucilage, and so on. See more on do cats need fiber.
Cats as strict carnivores
Felis silvestris, cat’s wild ancestors, are strict or obligate carnivores, while in the wild, they depending on animal flesh high in protein, moderate in fats, and low in carbohydrates. They eat mainly small rodents like rats and mice, birds, moles, rabbits, shrews, etc.
A study on feral cat dietary habits and data of their prey has “crude protein, crude fat and nitrogen-free extract (NFE) content of 52%, 46%, and 2% of metabolizable energy (%ME).”
Cats have a higher requirement for protein, taurine, cystine, arachidonic acid, niacin, arginine, vitamin A, and D than omnivores since their metabolism is different.
Just because they evolved prey high in protein, moderate in fats, and low in carbs, many veterinarians and scientists speculate that high carbs diets are detrimental to these animals linking them to diabetes, obesity, and other problems.
Furthermore, they use the fact that cats poorly metabolize glucose from carbs and their peculiar carbs metabolism to support the need to exclude carbohydrates in their diet or lower them.
Do cats need carbohydrates
Like dogs, carbohydrates aren’t an essential nutrient to cats. However, we know that dogs can eat carbohydrates, and they have the right enzymes to digest them except for dietary fiber, some of which are digested by colon microbiota. What about cats? Do they need carbohydrates or not?
Yes. Felines need cabs, but it is not an essential part of their diet. They can digest and utilize it efficiently. Let us look at digestion, glucose metabolism and show you that they can use it well and regulate their consumption.
1. Carbohydrate digestion
Like dogs, cats don’t have amylase in their saliva to help start the digestion of carbohydrates. Furthermore, their pancreas produces a lower level of pancreatic enzymes than dogs with a trace of isomaltase and low maltase activity and no lactase or sucrase.
However, they do have isomaltase, maltase, and sucrase in the small intestine to aid in carbohydrate digestion. Unlike other animals, their activity is low, and it increases from head to tail, unlike dogs that have optimum activity on the jejunum.
However, their ability to digest ground or cooked carbohydrates isn’t in double. A study found the digestibility of extruded cassava flour, corn, brewers rice, sorghum, lentils, and peas to digest more than 93%, with brown rice being highest.
A similar study on the digestibility of glucose, sucrose, dextrin, raw maize starch, and wood cellulose to be over 94% except for wood cellulose with glucose, sucrose, and lactose showing higher digestibility. The study further notes that cooking or fine grinding enhanced digestibility.
Therefore, since kibbles are cooked during extrusion, the cooking unlocks digestibility most carbs used to be over 95% digestible.
Unfortunately, poorly digestible carbs that don’t get digested in the small intestines will give colon microbes a substrate that may increase the colon and feces’ organic acid concentration. Also, it may result in diarrhea, flatulence, and bloating.
Therefore, ensure the carbohydrate source you offer to your cats is highly digestible and should cause any issue so long as the diet meets the minimum protein, fats, and other nutrients requirements.
Finally, compared to dogs, felines intestines are shorter, offering a smaller surface area to absorb monosaccharides and slower uptake of glucose.
2. Glucose metabolism
We know that glucose is the preferred energy source, especially by red blood cells, brain cells, and specialized cells found in the eyes, testes, and renal medulla.
Cats can get energy from fats, amino acids, and carbohydrates. They will metabolize fats (glycerol) and amino acids to glucose. They have active amino acids to glucose conversion mechanism, which is why they can thrive on proteins alone.
Therefore, they don’t have a physiological need for carbohydrates except when pregnant or nursing kittens, a time they need a lot of energy. While pregnant, lipoproteins cannot pass the placental barrier making simple sugars vital.
Perhaps another reason people feel that carbohydrates don’t belong to a cat’s digestion is that they don’t have glucokinase in their liver, which is vital for converting glucose to a usable form like dogs. Yes, carb metabolism in cats and dogs are different.
However, they have other enzymes such as hexokinase and others whose activity is higher, and their liver glycogen amount is comparable to humans.
3. Carnivores can regulate macronutrient intake
When fed on diets high on carbs, cats will restrict eating to ensure they don’t eat excessive amounts. This mechanism will also limit protein or fat take up, i.e., “cats have a ceiling for carbohydrate intake, which limits ingestion and constrains them to deficits in protein and fat intake (relative to their target) on high-carbohydrate foods,” shows a study.
A similar observation is made by another study that involved looking at the concentration of glucose and insulin during fasting and postprandial (after meal) when cats ate high-carbohydrate, low-protein (HCLP), or low-carbohydrate, high-protein (LCHP).
Higher glucose effectiveness (the ability of glucose to stimulate its uptake or suppress its produce under constant insulin concentration) in felines fed on high-carbs, low protein diet was noted.
Therefore, the study concludes that high-carb diets don’t cause obesity as assumed by many as they can adapt to varying micronutrients and control protein and carbohydrate metabolism whenever the need arises.
Benefits
We have shown you that cats can handle carbs, and it won’t cause any problem. It is time to look at some of the potential benefits or why people add them to their feline diets.
1. Alternative source readily available glucose
As we have seen above, can digest carbs, why not utilize glucose from carbs instead of relying on it from amino acids, a building block for various body tissue and organs, work as hormones, antibodies, and enzymes help replace and repair tissue.
2. Fiber benefits
Dietary fiber, soluble (fermentable) and insoluble (non-fermentable), is a carbohydrate type. Many benefits to cats include promoting gut health and digestion, managing weight, diarrhea, constipation, diabetes, and hairballs.
Additionally, fiber influences microbiome, intestinal water absorption, regulate gut function and may help with chronic renal failure.
Some of this fiber source includes whole grains, cereals, fruits, and vegetables like pumpkin, bananas, etc. This reality implies that you need to have these foods in feline diets.
3. May help in some conditions
Some conditions, such as chronic kidney disease (CKD) and liver disease, may require diets low in protein with CKD need those lower in phosphorus. Lower protein helps lower the uremic products that these organs have to metabolize or remove.
To make such diets, you need to increase carbohydrates or fats while lowering protein. High protein has higher phosphorus too. If you reduce one, you must increase others.
4. Help form and give texture dried food
Yes, it makes dry foods more economical and convenient, and grains or grain-free carbohydrates like legumes, cassava, and potatoes are more comfortable and cheaper to produce than protein. However, they don’t only serve as fillers in kibbles or cut on the cost alone.
For instance, the addition of gelatinized starch during cooking of kibble helps bind the kibble together as it is being extruded, i.e., gives it integrity so that it doesn’t crumble as well as texture and crunchiness. Texture has a significant influence on palatability. Meat alone wouldn’t be as crunchy.
5. Cats may like carbs
A study published at the Journal of Experimental Biology notes that when cats were offered equally palatable high-protein, high-fats, and high-carbs and diet balanced for macronutrients for 28 days, “dogs on average chose to consume most of their calories from fat (41%) and then carbohydrate (35.8%), whereas cats on average chose to consume most of their calories from carbohydrate (43.1%) and then protein (30%).”
Carbohydrate and diabetes
While it has been blamed for causing diabetes, dry foods high in carbs have been shown not to cause diabetes independently. One study blames inactivity and indoor confinement, while another study identifies gender, followed by low physical activity and breed without mentioning diet.
Only a single study links dry foods, low activity, and obesity as possible risk factors for feline diabetes mellitus in Swedish cats.
For felines that are already diabetic, while low-carbohydrate, high-protein may help reduce the risk factor of having diabetes since they don’t result in higher insulin concentration or postprandial glucose as those high in carbohydrates and low in proteins would.
However, ensure you don’t free-feed them since it will result in weight gain and higher energetic efficiency. Weight gain is a risk factor for diabetes. (1)
Also, note that reducing carbs means you have to increase proteins and fats. Unfortunately, protein, fats, and amino acids make the pancreas stimulate secretions that may harm felines with hepatic encephalopathy, active or acute pancreatitis, hepatic encephalopathy, or uremia signs occurring together with chronic kidney disease. Insulin therapy and wet renal diets may help felines with CKD and diabetic mellitus.
Contrary to this observation, there is a study that concludes that “starch has less of an effect on the cat postprandial glucose and insulin responses than on those of dogs and humans.” This revelation is perhaps a pointer that while all carbs are made from sugars, complex carbs and fiber may better instead of refined sugars.
Still, on diabetes, most vets recommend diets less than 7% on a dry matter basis in managing diabetes mellitus. Some evidence that amounts ranging from 5 to 26% of calories as carbohydrates are associated with diabetic remission and improved glycemic control with the highest reported remission rate associated with feeding 12% of calories as carbohydrates,” notes Veterinary Information Network.
Therefore, it is sensible to conclude that complex carbohydrates low in glycemic index and fiber may help manage body weight and glucose response.
All you need to do is avoid large meals and go for several smaller meals, which most cats prefer. This feeding system will avoid possible prolonged glucose spikes.
Does it cause obesity
Obesity may predispose felines to insulin resistance, diabetes mellitus, skin problems, lower urinary tract disease, osteoarthritis, other health issues, and carbs blamed for the increased obesity cases in these pets.
While animal factor contributes only a tiny percentage, diet, exercise, and other owner-controlled factors can cause obesity. Such include large meals, free feeding, high energy diets, giving table scraps on top of their foods, too many treats, highly palatable diets, and so on.
There is little evidence that commercial diets contribute to obesity except for a few dry foods or premium ones that are energy-dense, and carbohydrates aren’t one of the main concerns for obesity development.
While each cat has a different energy requirement, spaying or neutering, activity level may influence the energy they need.
Finally, both on obesity and diabetes, the fact that carnivores can regulate micronutrient intake as already see and because the amount of carbohydrates doesn’t influence disaccharidase activity a higher amount is unlikely to cause weight gain or diabetes
Food allergies and carbohydrates
Beef, milk products, and fish are the most common causes of allergies in cats, and they trigger more allergies than corn. However, it is correct to note that chicken, corn, soy, gluten, artificial coloring, preservatives, among others, are possible causes.
Some of the food allergies signs include gastrointestinal problems like diarrhea and vomiting, recurring ear infections, skin problems like bald patches, redness, itchiness, among others.
Let your vet investigate and identify the exact allergen and avoid it. He will also know if it is an allergy and intolerance and recommend ways to manage the allergy.
Carbohydrate in feline diets
Cat foods use grains like oats, corn, rice, wheat, rye, barley, and non-grain ones like peas, beans, lentils, chickpeas, potato, tapioca, sweet potatoes so on.
These diets have carbs primarily because it’s a source of energy (primary source). Other factors include building blocks for vitamin C and some non-essential fats.
There are no particular studies that condemn any highly digestible carbohydrate in feline diets so long as it meets the diet meets nutritional profile for the specific life stage, i.e., a complete and balanced.
The American Association of Feed Control Officials and The European Pet Food Industry Federation require that feline diets have a “minimum protein (25% Metabolizable energy) and fat (20%Metabolizable energy),” (2) giving an allowance of carbs to have up to 55% metabolizable energy.
However, feline foods have 20% and 40%ME with grains, legumes, potatoes, sweet potatoes, and tapioca, mainly starches used as carb sources.
On the other hand, most wet foods are higher in protein and lower in carbohydrates (less than 10%) and provide better hydration. Cats get water from their diet as they are not excellent water drinkers, and wet foods will avoid dehydration.
Kibbles are high in carbohydrates, but it shouldn’t be an issue so long as the minimum amount of fats and protein is met. They are easier to store, have a longer shelf life, and some pets prefer them over wet diets.
Alternative diets
There are alternative diets such as home-cooked, raw-meat based, bone and raw food, vegan and vegetarian diets that are said to have benefits compared to heat-processed one. They have a better digestibility, are higher in crude protein and gross energy, and so on.
However, they do have the risk of pathogens like salmonella, campylobacter, E. coli that will affect your pet and possibly you since these pets shed them in their feces. Also, those with bone may cause obstruction or injuries (by bone fragments), and those contaminated with raw thyroid tissue may cause exogenous thyrotoxicosis
Conclusion
Cats can efficiently digest, absorb, and use carbohydrates in their diet. While they have a lower enzymatic activity to digest carbohydrates and their liver enzyme activity is different, feeding them small meals several times a day, which is their favored pattern, will work well with the number of carbs in the diets.
Low-carb, raw diets, freeze-dried, antioxidant-rich, and so on are some of the terms that manufacturers use to sell their products. However, don’t be swayed. Always look at the product label, especially guaranteed analysis.