Garlic, a common ingredient in human food, often raises concerns among dog owners. You might have encountered warnings online or even from veterinary professionals cautioning against garlic consumption for dogs, labeling it as a poisonous substance. If you’re here, it’s likely because you prioritize your dog’s well-being and seek clarity on whether garlic is truly harmful. We understand your concern and are here to share what evidence-based research reveals about garlic and its effects on dogs.
Many misconceptions surround garlic and its supposed toxicity to dogs. It’s crucial to understand these myths and discover the potential health benefits that garlic can actually offer our canine companions.
The question arises: how did the notion of garlic being toxic to dogs become so widespread when scientific literature lacks substantial evidence to support this claim? The conversation around garlic and dogs has become somewhat distorted due to misleading interpretations of research. This misinformation often stems from studies that examine the effects of garlic extracts, administer excessively high doses, and employ unnatural delivery methods. Researchers seldom utilize fresh garlic in studies on dogs because measuring the variable effects of whole plant medicine poses significant challenges in controlled experiments.
Evidence-based research often struggles to incorporate the “food as medicine” approach, which considers the holistic benefits of natural ingredients.
When it comes to your dog’s health, whether for preventative care or treatment, access to accurate and current information about both safety and benefits is paramount. Garlic, a herb with a long history of beneficial use and even approved for use in pet food by the FDA, remains under scrutiny. Despite a 2004 follow-up study that reinforced the recommendation of garlic for dogs by a majority of scientists involved in an earlier 2000 Japanese study, the negative reputation persists. The 2000 Japanese study, conducted by K. W. Lee et al., is often cited as the origin of garlic’s harmful reputation. However, this study involved feeding dogs an extreme dose of 5 grams of garlic per kilogram of body weight daily. To put this in perspective, this amount is equivalent to feeding a 75 lb Golden Retriever approximately four whole heads of garlic (or 60 cloves) or a 10 lb dog about 23 grams of garlic (6 to 8 cloves) before any adverse effects might be observed. It’s crucial to understand that this is an exceptionally high and unrealistic amount, and certainly not a recommended dietary inclusion!
Similar to herbs like nettle and turmeric, scientific evidence suggests that small, appropriate doses of raw garlic can be beneficial and act as a medicinal food for dogs.
But conflicting information persists, and the internet and even some veterinary advice may still raise concerns.
This article aims to debunk the myth of garlic toxicity in dogs by exploring essential information, including:
- The Health Benefits of Garlic for Dogs
- Reasons Behind Dog Owners’ Avoidance of Garlic
- The Misinterpreted Research Fueling Garlic Misconceptions
- Recommended Daily Garlic Dosage for Dogs
- The Efficacy of Garlic Supplements
- Preparing Garlic for Canine Consumption
- Understanding Garlic Poisoning in Dogs
Let’s begin by examining the beneficial aspects of raw garlic for dogs.
Garlic (Allium sativum) is a vegetable belonging to the Allium family, which also includes onions, chives, leeks, and shallots – a point of confusion that we will address shortly.
Throughout history, garlic has served as a culinary ingredient and a remedy for various ailments in both humans and animals. Ancient Egyptians routinely provided garlic to laborers to enhance their immunity, while traditional Chinese medicine practitioners and Native American healers frequently employed garlic to treat conditions ranging from scurvy to earaches.
Garlic boasts a rich composition of nutrients, including inulin, amino acids, sulfur compounds, zinc, potassium, and phosphorus. It also provides vitamins A, C, calcium, magnesium, manganese, selenium, germanium, and B-complex vitamins. While many of these components contribute to detoxification processes within the body, garlic’s renowned medicinal properties are largely attributed to its bioactive compounds, Allicin and Ajoene.
Garlic contains sulfur-containing compounds, notably alliin, a sulfoxide, and alliinase, an enzyme. When garlic is chopped, crushed, minced, or chewed, the alliinase enzyme activates and interacts with the alliin protein to produce allicin, the primary therapeutic component of garlic. Heat can deactivate enzymes, so to maximize the therapeutic value, it’s recommended to wait at least ten minutes after chopping garlic before cooking, allowing the enzyme to fully react with the alliin. Importantly, allicin itself is heat-stable.
1. How Garlic Helps Dogs
Garlic’s potent energy has a warming effect on the body. Pungent herbs like garlic promote energy flow upwards and outwards to the body’s surface, enhancing circulation. Garlic also exhibits a particular affinity for the lungs, large intestine, spleen, and stomach, supporting their functions.
Garlic aids in detoxification. It fosters the growth of beneficial bacteria in the digestive tract while inhibiting harmful bacteria. It’s particularly beneficial during fall, winter, and early spring to support detoxification and balance the digestive system.
As a liver support agent, garlic assists in breaking down waste products before they enter the bloodstream. It also promotes nutrient assimilation and waste elimination throughout the digestive system. Garlic is well-known for its detoxifying properties, which can help the liver eliminate toxins from the body efficiently.
The amount of garlic included in Volhard Diets is carefully measured to be small yet sufficient to provide these benefits. With over 40 years of experience, we have not encountered any health issues in dogs related to garlic consumption in our diets.
But the benefits extend further…
- Prevents blood clot formation (anti-platelet activity)
- Reduces cholesterol buildup (anticholesterolemic effect)
- Dilates blood vessels (vasodilator)
- Helps prevent tumor formation (anti-tumor properties)
- Stimulates the lymphatic system to remove waste
- Exhibits antibiotic, antifungal, and antiparasitic properties. Raw garlic (and garlic extracts) are utilized in holistic veterinary practices for their antimicrobial, antiseptic, and antibiotic qualities. Among its various applications, garlic is particularly valued as an anthelmintic (deworming agent) for pets.
- Research has identified anticancer compounds within garlic.
Garlic can also contribute to lower blood sugar and cholesterol levels. It’s often recognized as “good for the blood” due to its traditional use in combating blood infections and reducing blood pressure.
Beyond these health advantages, garlic offers additional benefits. It can act as a flea and tick repellent for dogs. Fleas are more attracted to animals with weakened immune systems – the very young, elderly, sick, or unhealthy. Flea infestations are less common in healthy, immunologically robust dogs. Many dog owners who feed Volhard Dog Nutrition diets report never encountering fleas on their pets.
Garlic can be a valuable tool in flea and tick prevention when incorporated into your dog’s diet during flea and tick season. It takes approximately two weeks for garlic to build up in a dog’s natural coat oils, so it’s advisable to start feeding garlic before the start of the bug season. Garlic’s tick-repelling properties in pets are supported by research indicating anti-tick qualities in humans. The sulfur compounds in raw garlic are excreted through the dog’s skin, effectively repelling these insects. Since it takes a couple of weeks to become effective, starting garlic supplementation before tick season is recommended.
As mentioned earlier, Allicin provides significant benefits.
Here are some well-established benefits of raw garlic, primarily studied in human participants, but expected to translate to canines as well:
The benefits include:
- Antibiotic, antifungal, and anthelmintic properties
- Immune system support
- Protection against the common cold
- Reduction of blood pressure and elevation of anti-clotting factors in the blood
- Reduction of internal inflammation and lowering of cholesterol, decreasing the risk of cardiac diseases
- Potential to mitigate the effects of Alzheimer’s Disease and Dementia
- Detoxification of heavy metals within the body
It’s important to note that garlic may have contraindications with certain medications, which are expected to be similar across species. These will be discussed at the end of this article.
2. Why Do Dog Owners Avoid Garlic?
Despite the numerous benefits, why do concerns about garlic’s safety for dogs persist?
The primary reason for this apprehension is garlic’s classification within the Allium family, which also includes onion, leek, chive, and shallot. While all these plants contain various sulfur-based compounds, onion, leek, chive, and shallot contain significantly higher concentrations of thiosulfate, the compound of concern. Thiosulfate is indeed toxic to canines, although not to humans.
When ingested in large quantities by dogs, thiosulfate can cause oxidative damage to red blood cells, leading to the formation of “Heinz bodies.” These damaged red blood cells are recognized and removed from circulation by the body. Over time, this process can result in Hemolytic Anemia and, in severe cases, may even be fatal.
3. What Was the Flawed Research That Caused the Garlic Misunderstanding?
Garlic’s negative reputation began to solidify around 2000 with the publication of a research paper examining garlic’s effects on dogs. Although the dogs in the study did not exhibit outward signs of toxicity, subtle changes were observed in their red blood cells. The researchers concluded, “We believe that foods containing garlic should be avoided for use in dogs.” This statement triggered widespread rumors and the perception that garlic could be deadly for dogs. However, this reaction was arguably premature and overly severe. Many people only encountered summaries of the study and drew hasty conclusions. A closer examination of the detailed results reveals a more nuanced picture.
It’s crucial to recognize that this study employed extraordinarily high doses of garlic, far exceeding typical dietary intake, for research purposes. While changes in blood parameters were noted, none of the dogs developed hemolytic anemia. The study’s ultimate conclusion was that such extreme garlic ingestion over a limited period might lead to hemolytic anemia.
The excessive amounts of garlic administered in this study significantly skewed the results, rendering the experiment’s findings largely irrelevant to the medicinal use of raw garlic in a dog’s diet at recommended doses. This type of flawed research should not be used to discourage the use of appropriate medicinal doses of raw garlic for dogs.
4. How Much Garlic Can Dogs Eat Daily?
Now that we’ve addressed the misconceptions and are open to considering garlic’s medicinal potential, let’s discuss appropriate dosages.
It’s essential to remember that excessive intake of anything, even beneficial substances, can be detrimental. Minerals like salt, vitamin D, and zinc, vital for health, can become harmful in excessive amounts. The same principle applies to garlic for dogs. In large doses, garlic, like many other substances, has the potential to be toxic. Moderation is key.
Note: As with any dietary supplement, it’s crucial to start with a small dose and gradually increase to the full recommended dosage. Avoid initiating supplementation with the full dose immediately.
Another approach is to offer a properly dosed amount of garlic alongside your dog’s food and allow them to self-select if they feel they need it.
Many veterinary practitioners and authors, including Wendy Volhard, follow the dosage recommendations outlined in Juliette de Bairacli Levy’s book, The Complete Herbal Book for the Dog. Her guidelines are as follows:
- 10 to 15 pounds – ½ clove
- 20 to 40 pounds – 1 clove
- 45 to 70 pounds – 2 cloves
- 75 to 90 pounds – 2½ cloves
- 100 pounds and over – 3 cloves
A 2008 report by the National Research Council offers more conservative dosage information. While the committee preparing the report couldn’t establish a definitive safe upper limit for garlic intake in dogs, cats, and horses, they utilized available research to recommend a range of acceptable intakes based on historical safe intakes (HSI) and estimated presumed safe intakes (PSI).
Based on an average clove weight of 3g, the PSI for a 50 lb dog is 1.2 g or 0.045 ounces/day, approximately equivalent to ½ clove per day.
Recommended Garlic Dose Using Measuring Spoons
Using standard measuring teaspoons, the following amounts of raw garlic per day are recommended based on your dog’s weight:
- 5 lbs: ⅙ tsp
- 10 lbs: ⅓ tsp
- 15 lbs: ½ tsp
- 20 lbs: ⅔ tsp
- 30 lbs: 1 tsp
5. Are Garlic Supplements Just As Beneficial?
I strongly advocate for feeding fresh, raw garlic to dogs to maximize its benefits. Dried garlic supplements often prove less effective, and chemically produced garlic supplements might even be detrimental. If you choose to use garlic supplements for your dog, opt for garlic extracts. Powdered garlic, and indeed encapsulated dry herbs in general, tend to be weak and less potent. “Deodorized” garlic lacks active allicin (enzymatic activity is associated with garlic’s characteristic odor), and tableted supplements may contain binders that could weaken digestive processes or even be potentially toxic. Glycerol-suspended garlic products, while palatable, can create a moisture barrier that hinders absorption by mucous membranes and cells. Cold-pressing garlic is the optimal method to preserve and maximize its beneficial properties.
Certain supplements, such as Brewer’s Yeast combined with garlic, are particularly beneficial for promoting healthy skin and coat, in addition to the other advantages already mentioned. Both garlic and Brewer’s Yeast are key ingredients in the Volhard NDF2 diet!
6. The Preparation of Garlic for Dogs
Incorporating fresh, raw garlic into your dog’s daily diet is the most effective way to boost their immunity.
How can you do this?
- First, always prioritize fresh and organic garlic. Avoid canned (cooked) or processed garlic commonly found in supermarkets, as these may contain preservatives for extended shelf life.
- Second, peel the garlic clove and then mince, chop, or crush it. Use the prepared garlic within 10 minutes to maximize its medicinal benefits. Pre-peeled and chopped jarred garlic lacks medicinal qualities.
- Third, introduce garlic to your dog’s food gradually. Increasing the dose over several days will help your dog adjust to the taste of garlic.
There are specific situations where caution is advised when feeding garlic to dogs:
Drug Interactions: Garlic can interact with certain types of medications. Avoid giving garlic to dogs with pre-existing anemic conditions. Exercise caution when dogs are taking the following medications:
- Heart medications
- Immunosuppressants
- Chemotherapy drugs
- Blood thinners
- Blood pressure medications
- Insulin therapy
Note: Some dog breeds exhibit greater sensitivity to garlic than others. Consider your dog’s breed when determining the appropriate dosage. For instance, Japanese breeds like Shiba Inus and Akitas tend to be more sensitive to garlic. In such cases, consulting with your veterinarian is advisable.
7. Garlic Poisoning in Dogs
Garlic poisoning in dogs is exceptionally rare. It’s highly unlikely that a dog would voluntarily consume 100 cloves of garlic in one sitting. Much of the fear surrounding garlic stems from misinterpreted research and misinformation, leading pet owners to believe that even a tiny amount of garlic their dog might ingest could be harmful, which is generally not the case.
The best preventative measure is to restrict your dog’s access to all members of the allium family, unless you are intentionally providing them. Keep onions, leeks, and other potentially harmful alliums out of your dog’s reach. If your dog is known to counter-surf, secure these items in cupboards or pantries, especially those not requiring refrigeration. This control over garlic access allows you to manage your dog’s garlic intake completely.
Conclusion
Based on extensive research, we confidently recommend incorporating small amounts of garlic into your dog’s diet regularly, especially if your dog has health concerns where garlic might be beneficial. If you are feeding Volhard NDF2 or the AM/PM diet, garlic is already included, and additional supplementation is generally unnecessary unless you are specifically using garlic to support the body during times of illness or imbalance. If your dog has a pre-existing health condition, consulting with a veterinarian before introducing garlic is always a prudent step.
Volhard Dog Nutrition and our team of expert nutritionists offer online consultations to guide dog owners in understanding the best nutritional approaches for their dogs! Connecting with a Volhard nutritionist can illuminate the critical link between healthy food, a healthy body, and a healthy mind in dogs. If you’re interested in learning more, please visit our consultation page!
