Dogs have specific nutritional needs. Nutrition for dogs provided by all the relevant macronutrients and micronutrients is discussed. We consider the role a dog’s unique digestive system plays as well.
Our team at fitdogster.com spent over 35 hours researching nutrition for dogs – internet, social media, and speaking to pet nutritionists and vets. So let’s get started!
A Dog’s Digestive System – How it Works
Macronutrients/Micronutrients
Water
Proteins
Carbohydrates
Fats
Vitamins
Minerals
To Sum It All Up
A Dog’s Digestive System – How it Works
Dogs are generally considered omnivores but also have many traits of scavenging carnivores. Scavenging carnivores in the wild feed on leftover carcasses and fallen plants.
A dog’s pancreas is an important part of its digestive system. It produces digestive enzymes to break down fats, proteins, and carbohydrates. In dogs, this organ is designed to most efficiently break down animal protein and fat.
Carbohydrate digestion starts in the mouth for omnivores and herbivores, where a digestive enzyme Amylase is produced in their saliva. The purpose of this enzyme is to break down carbohydrates. Dogs do not have this ability and like carnivores, carbohydrate digestion takes place in the small intestine.
Dogs also process food faster than typical omnivores. This is due to their large stomach size and short digestive tract. Food is in their stomach longer with these stomach acids. That longer exposure allows protein, fats, and even bone to be broken down.
This also destroys harmful bacteria, like those in raw meat. Other omnivores like humans cannot prevent the spread of these harmful bacteria in this manner.
A plant-based diet can provide dogs with the basic nutrients they need to live, but ingredients have to be chosen carefully and require the right supplements too.
Diets that include animal protein provide nutrients that are easier to digest. Most commercial pet foods use protein from both plant and animal sources which can offer a wider variety of nutrients. This allows the dog to thrive nutritionally.
Macronutrients/Micronutrients
There are two different types of nutrients required for your dog’s diet.
- Macronutrients are what comprise dog food: protein, carbs, and fat. Each is digested differently and used to supply energy as well as nutrition to all parts of a dog’s body.
- Micronutrients are the nutrients that the body gets from digesting macronutrients. Vitamins, minerals, and amino acids are all micronutrients.
Before we get into these let’s discuss another important component of a dog’s nutritional needs – water.
Water
Water comprises roughly 75% of an adult dog’s lean body mass. Water dissolves and transports nutrients to the cells; helps regulate body temperature; hydrolyzes protein, fat, and carbohydrates for digestion; cushions the organs and nervous system; flushes waste.
According to PetMD, dogs should drink approximately one ounce of water per pound of body weight each day. But, be sure to consult your veterinarian. A dog’s water requirements vary based on health, activity level, and environmental temperature. Most dogs self-regulate their water intake to meet their needs. Dogs fed high-moisture foods typically drink less than kibble-fed dogs.
A 10% decrease in body water can cause serious illness, while a 15% loss can result in death. So dogs should always have access to clean, fresh water!
Proteins
Protein plays a role in every part of your dog’s body. Proteins are complex molecules made up of amino acids, the building blocks for cell growth, maintenance, and repair. One of the most significant uses for protein in companion animals is for the maintenance of fur and hair. This can use as much as 30% of daily protein consumption.
All enzymes are made up of proteins too. This makes proteins essential to your dog’s immune system and hormone production.
Dogs are able to create some amino acids on their own, but there are 10 amino acids that they can’t make. These are called essential amino acids, and they must be obtained through diet. Many systems in your dog’s body will not function properly without these essential amino acids.
Animal proteins are complete. This means they contain all 10 of the essential amino acids, and even some non-essential ones. Some essential amino acids can be found in plant protein. However, only a very limited number of plant proteins contain all 10 essential amino acids. The table below summarizes the 10 essential amino acids and how each one enables a dog to function.
Amino Acid | Function |
| Arginine | Blood vessel dilation and improves circulation |
| Histidine | Maintains hemoglobin, improves oxygen and circulation |
| Methionine | Aids in keratin synthesis for healthy skin and coat |
| Threonine | Aids in energy production |
| Isoleucine | Healthy muscle development and protein synthesis |
| Leucine | Healthy muscle development and protein synthesis |
| Valine | Healthy muscle development and protein synthesis |
| Phenylalanine | Thyroid and adrenal gland function |
| Lysine | Aids in protein synthesis for growth and development |
| Tryptophan | Promotes hormone production like serotonin and melatonin |
Even if only one of these “essentials” is deficient, as Lowell Ackerman, DVM, explains, the body cannot make specific proteins effectively.
Meats, most meat-by-products, and dairy products have high biological values. This measures how efficiently an animal can use them for tissue protein synthesis. However, the biological value of most plants is low. They have inadequate amino acids and are harder to digest.
Carbohydrates
Simply stated, dogs do not need carbohydrates. Their bodies can get energy from protein and fats alone. That said, carbohydrates that can be broken down by the digestive system and converted to glucose can also be a source of energy. Since some carbs can be better than others so it’s worth a short discussion.
Absorbable Carbohydrates
Absorbable carbohydrates are a quick energy source. Absorbable carbs have a rapid effect on blood sugar levels, so too many absorbable carbs in their diet can lead to unused energy that needs to be stored. Good examples are sugar, honey, molasses, caramel, and beet pulp.
Limit the amount of this type of carb to reduce unnecessary weight gain, excess sugars, or unused energy. These carbs can contribute to digestive issues since these sugars feed bacteria, good and bad.
Digestible Carbohydrates
Digestible carbohydrates (starches), take longer to digest. Enzymes in the small intestine break down starches into an absorbable format. Starches are used for energy, like absorbable carbs. Examples found in pet food include potatoes, rice, wheat, or corn.
Despite taking longer to digest, starches can still have a notable effect on blood sugar if excessively consumed.
It is harder for dogs to digest starches since they lack the Amaylase enzyme in their saliva.
Fermentable Carbohydrates
Fermentable carbohydrates (or prebiotics) are used by the bacteria in your dog’s intestines as a source of food. Prebiotics ferment during digestion, and produce sugars that feed existing bacteria in the gut.
Common forms of prebiotics found in off-the-shelf dog foods are alfalfa and chicory root. Also, adding prebiotics to a dog’s food will help to replenish your dog’s natural levels of healthy bacteria and improve digestion. These are a healthy carb source but overfeeding prebiotics can still cause problems.
Non-Fermentable Carbohydrates
Non-fermentable carbohydrates are simply a source of fiber. Fiber regulates digestion and does not break down into sugar. Fiber is critical for healthy digestion.
Soluble fiber attracts water, slows digestion, and contributes to a feeling of fullness. Examples are oatmeal and berries.
Insoluble fiber adds bulk and speeds movement through the digestive system. An example is brown rice.
A great source of fiber for a dog’s diet is pumpkin. Pumpkin is both a soluble and insoluble fiber. Since it can regulate the speed of digestion, it can be used for both diarrhea and constipation relief.
Simple Carbohydrates vs Complex Carbohydrates
Based on how quickly they digest and its nutritional value, carbohydrates can also be classified as either simple or complex.
Simple Carbohydrates
Simple carbohydrates (aka simple sugars) have less value in your dog’s diet than complex carbohydrates. They do not offer much nutrition apart from a quick energy source. Simple sugar is made of a single sugar molecule, like glucose or fructose.
Complex Carbohydrates
Complex carbohydrates take longer to digest and release sugar into the blood slower. These are typically comprised of many sugar molecules that are linked together. These molecules have to be separated, which leads to a slower release into the blood.
Complex carbohydrates also may contain fiber and other nutrients. This makes them more nutritious.
Opt for complex carbohydrates over simple carbohydrates, but too many of either can still cause the food to be unhealthy. Dog food needs to be rich in meat and fat with a limited amount of complex carbohydrates.
High-quality dog food should primarily include carbohydrates that have a low GI (glycemic index) value. Foods considered high glycemic releases sugar into the bloodstream quickly. This causes your dog’s blood sugar levels to spike, and rapidly drop when the sugars are used or stored by their body.
Quick drops in blood sugar can contribute to a feeling of hunger and can lead to overeating and weight issues. It’s best to avoid foods that use a lot of high-glycemic ingredients.
Wheat and corn are two common dog food ingredients that have a high glycemic rating. Peas and quinoa are both low glycemic and release sugars into the bloodstream at a more steady rate.
Focus on low glycemic ingredients whenever possible, and make sure that all carbohydrates are fed in moderation. Foods with a high meat inclusion, high protein, and low carbohydrates are going to have a lesser effect on blood sugar levels than a carb-heavy diet.
Fats
Fats provide the most concentrated source of energy in a dog’s diet. They also supply fatty acids which are important to sustaining normal, healthy cells. In addition to protein, fats provide for a diet’s taste and absorption of fat-soluble vitamins A, E, D, and K.
Fat has essential fatty acids or EFAs. Because they make up an important part of every cell, they are also required by animals.
Omega-3 fatty acids and Omega-6 fatty acids both are a form of polyunsaturated fat that the body derives from food. Listed below are all of the essential fatty acids, the type of essential fatty acids it is, the primary sources for the fatty acid, and what they support nutritionally for a dog’s body.
Eicosapentaenoic Acid (EPA)
Type: Omega 3 Fatty Acid
Common Source: Fish/Fish Oils
Function: Supports cognitive, growth, retinal, heart function, reduces inflammation, supports mobility, pain management, and skin and coat health.
Docosahexaenoic Acid (DHA)
Type: Omega 3 Fatty Acid
Common Source: Fish/Fish Oils
Function: Supports cognitive, growth, retinal, heart function, reduces inflammation, supports mobility, pain management, and skin and coat health.
Alpha-Linolenic Acid
Type: Omega 3 Fatty Acid
Common Source: Animals & plant sources, fish oils
Function: Can produce EPA and DHA less efficient, < 20% converted
Linoleic Acid
Type: Omega 6 Fatty Acid
Common Source: Plant oils such as safflower, flaxseed, and olive oil
Function: Supports skin and coat, bone density, and reproductive health
Arachidonic Acid
Type: Omega 6 Fatty Acid
Common Source: Poultry, animal organs and meat, fish, seafood, and eggs
Function: Supports inflammation to prevent pathogens, bacteria, anything else attacking the body
Essential fatty acids maintain the vital systems in your dog’s body, so it is imperative they are provided in your dog’s diet. Each essential fatty acid has its own unique benefits and works best when used cooperatively.
The optimal ratio of Omega-3 fatty acids to Omega-6 fatty acids for dogs is between 1:5 – 1:10. This ratio enables each fatty acid to work most efficiently. Even though fatty acids are supplemented in most dog foods, the ratio isn’t always right for every dog. For instance, dogs with allergies or skin issues can benefit from more Omega 3’s in their diet. Also, make sure sure the fats are from a quality source. So do a little extra homework if your dog has special health issues!
Canine obesity, caused by excessive calories and low activity lifestyle, increases the chances of many weight and age-related conditions. One such condition to be aware of is acute pancreatitis. It is the sudden inflammation of the pancreas and has been tied to obesity and poor diet. Pancreatitis is dangerous and can become life-threatening if left unresolved.
Vitamins
Fresh, wholesome food provides your dog with the best source of vitamins, and organic substances required for normal functioning. Only a small amount is needed. Vitamins play several important roles, including regulating calcium and phosphorus levels (D); boosting the immune system (A); serving as antioxidants (C and E); enabling the blood to clot (K), and maintaining nervous system function (B12). They are also important in the conversion of calories to energy.
Minerals
Minerals are inorganic nutrients. They make up less than 1 percent of a dog’s body weight but are also essential to many important functions – growth, strong bones, and teeth. They are categorized as macrominerals or microminerals. It is important to note that two of the macrominerals, calcium, and phosphorus, must be in balance and given in the correct ratio. The optimal calcium-to-phosphorus ratio is between 1:1 and 2:1. Microminerals (also known as trace minerals) serve very important functions as well. Balance is also critical with all minerals because they interact; too much of one can interfere with the absorption of another.
To Sum It All Up
Making sure your dog maintains a well-balanced diet is essential to his growth, development, and daily functioning. Read labels carefully to make sure you’re getting what you think you’re getting for your dog’s diet. See some high-quality suggested dog food recommendations by breed. In addition, if your dog has any special health issues, take care to supplement his diet as needed.
