diet and behaviors

Find out how certain dietary nutrients and calming supplements may curb aggression, anxiety and other unwanted behaviors in dogs.

Did you know that nutrition plays a role in canine behavior? Aggression, anxiety, begging, destructiveness, excessive barking and house soiling are just a few of the unwanted behaviors dog owners sometimes contend with. Socialization and training are definitely a big part of helping these dogs, but alterations to the diet and the addition of calming supplements can also be beneficial.

Certain nutrients may improve problem behaviors 

Behavior in animals (including humans) is regulated in part by neurotransmitters and hormones; these have precursors, chemical compounds that precede them in metabolic pathways. Making these precursors more or less available may make a difference in a dog’s behavior.


Tryptophan is the precursor of serotonin (a neurotransmitter). The presence or absence of tryptophan is thought to affect aggression and stress resistance in dogs. Tryptophan is a large neutral amino acid (LNAA) that can cross the blood-brain barrier, depending on how much free tryptophan and other LNAAs are available in the body.

Increasing dietary tryptophan through supplementation can increase serotonin in the brain, which has been shown to reduce aggression and improve recovery from stress in some animals. Even though tryptophan is found in protein-containing foods, it is in relatively small supply compared to other LNAAs. In fact, a high fat and protein diet actually decreases the ratio of tryptophan to other LNAAs. This is why dietary supplementation of tryptophan is recommended.


Tyrosine is a precursor of catecholamines (hormones produced by the adrenal gland) and may also affect aggression and stress resistance. Another amino acid, tryosine has been shown to have a beneficial effect on stress in humans and other animals. Along with iodine, it is also needed for adequate thyroid hormone production. Reduced amounts of tryosine can have a negative impact on thyroid hormone production, influencing metabolism, immune health and behavior, contributing to depression and aggression.

Unlike tryptophan, tyrosine is usually found in high concentrations in high protein meals.

Docosahexaenoic acid (DHA)

DHA is a polyunsaturated fatty acid (PUFA) with a beneficial effect on inflammation and cognition in humans and animals. Increased PUFA into the cellular membranes of the brain supports an improved flow of neurotransmitters between cells.

Studies indicate that DHA-rich diets improve learning ability while diets deficient in DHA have the opposite effect. In a large-scale study of puppies fed an enhanced-DHA diet, the pups made fewer errors during training and had a higher training performance index than puppies fed a diet containing normal quantities of DHA.

Since a diet rich in Omega-3 essential fatty acids, including DHA, has so many other health benefits for pets, any positive impact they may have on a dog’s behavior is an added bonus.

Two approaches that aren’t advised

In our efforts to curb certain undesirable dog behaviors through nutrition – especially if those behaviors are the result of natural canine instincts – we must ensure we aren’t creating ill health in other areas. For example:

1. Low protein diets don’t curb aggression

A few studies conducted outside controlled experimental environments have been used to measure the impact of lower protein diets on aggressive dogs. The results are largely inconclusive.

When I lecture with pet food formulator Steve Brown, we use his Ancestral Diet Database and Pet Food Formulator software to demonstrate how high fat meats (less than 85% lean) in a homemade diet can easily cause tryptophan deficiencies. If you are making your own dog food, it’s very important to use lean meat and make sure you follow a nutritionally balanced diet. I would never recommend reducing the amount of high quality protein in an attempt to modify behavior, but I strongly advise following a recipe in which the amino acid profile is evaluated to be adequate, or in my opinion, optimal.

Additionally, feeding a grain-based diet will induce an insulin release (to balance high blood sugar after ingesting a high carb diet), and in turn, a cortisol release (to balance low blood sugar). While this approach is likely to make your dog more sedate after a meal, I don’t believe that loading dogs with carbs to produce post-meal sedation is an appropriate behavior modification tool.

2. Increased fiber doesn’t banish begging behaviors

Whining and begging for food, stealing food, trash and dumpster diving, and other activities that seem to stem from feelings of hunger can be more than a little annoying. This has led to the misguided notion that a fiber-rich diet, which is presumably more satiating to dogs, might play a role in curbing undesirable food-seeking behavior.

I absolutely disagree with this notion and would never encourage anyone to feed their dog more dietary fiber as a way to correct food-seeking behavior. Fiber is not species-appropriate nutrition for carnivores. Excessive amounts of fiber can block absorption of healthy nutrients into the small intestine; fiber acts as a mechanical barrier, preventing trace minerals, vitamins and antioxidants from getting to and through the walls of your pet’s gastrointestinal tract.

Chances are, if a dog’s food-seeking behavior isn’t primarily learned (i.e. it has been rewarded in the past), it’s coming from a lack of adequate protein at the cellular level. Chronic deprivation of species-appropriate nutrients to the cells can result in feelings of constant hunger.

Calming supplements

In some instances, despite a balanced, nutrient-dense diet and rigorous exercise, some dogs may still exhibit occasional signs of anxiety or restlessness. In these instances, I have found the following natural supplements to be beneficial.

  • Organic holy basil (Tulsi) is an adaptogenic herb that enhances the body’s natural response to physical and emotional stress.
  • L-theanine stimulates alpha brain waves that help with mental alertness, yet is simultaneously calming.
  • Organic rhodiola rosea is another adaptogen that acts in non-specific ways to increase resistance to stress without disturbing normal biological functions.
  • Ashwagandha (Indian gGinseng) is also an adaptogen – it can help your dog’s body better manage physical, chemical and environmental stressors.
  • Chamomile is a well-recognized herb with calming qualities.
  • 5-Hydroxytryptohan (5-HTP) is created when tryptophan converts into serotonin, and promotes concentration and feelings of well-being. When levels of serotonin are too low, fear, aggression and anxiety can emerge.
  • GABA (Gamma-Aminobutyric acid) is an important central nervous system neurotransmitter. Studies show that too little GABA can contribute to feelings of panic and anxiety.
  • Vitamin B6 supports a healthy nervous system and mood, and helps with serotonin production.

If your dog is displaying behavioral issues, positive obedience training and behavior modification, along with a good exercise program, may all be in order. In addition (with the help of an integrative or holistic vet who can tailor a protocol specific to your dog and his needs), consider making some changes to his diet or introducing some supplements to help calm and balance him.