What To Feed Your Senior Rat to Keep Them Healthy

This article contains affiliate links, and we may earn a commission at no cost to you if you choose to purchase through these links. I never recommend products that I do not trust or will not advise my veterinary clients and patients to use.

A pet rat is considered a senior from around 18 months old. That means that they can spend nearly half of their life as a senior. Rats already have such short lifespans compared to us, so let’s have a look at the evidence-based foods you can add to your rat’s diet to help keep them around and healthy for as long as possible.

Senior or older rats commonly have underlying health conditions such as kidney disease. Certain supplements, such as Omega 3 fatty acids, are beneficial in supporting reduced kidney and heart function. In addition, a diet high in antioxidants such as Lipoic Acid, vitamins A and E helps reduce oxidative stress on aging cells.

The types of food you feed your older rats are even more important than what you feed your youngsters. Unfortunately, it is sometimes easy to forget that senior rats have much more complex and specific dietary requirements than young and growing rats until they become ill. Luckily, there are several extensively researched ingredients that can help keep older rats feeling their best for longer.

Special Dietary Considerations for Senior Rats

When considering what nutritional support a senior rat will need, it is best to consider the health conditions we most commonly see in older rats as well as how the metabolism may change with age.

Apart from respiratory conditions, which are common across all ages of rats, kidney disease and cancer are probably among the most common reasons an older rat’s health starts to decline. Heart disease is also diagnosed far more frequently in older rats compared to youngsters.

Be Kind to the Kidneys

Now, not every senior rat will develop a heart condition or cancer but nearly every aging rat will have some degree of declining kidney function as they age.

Chronic kidney disease symptoms may only show up after more than 60% of the kidney function has been lost so it often goes undiagnosed for a long time after kidney function has started to decline. For this reason, it is best to feed a senior rat as if it has declining kidney function.

Nearly every senior rat will have some degree of declining kidney function.

I am not going to dive into the details of kidney disease in this article but it will be helpful to understand the basics of how diet may affect the kidneys. The kidneys work very hard to maintain electrolyte and fluid balance, normalize blood pressure and excrete waste products produced by normal metabolism and digestion.

For this reason, a kidney-kind diet is low sodium, low phosphorus, moderate protein. Avoid human foods high in salt such as crackers or popcorn. Examples of high-phosphorus foods to avoid is milk products such as cheese, seeds, nuts and wholegrain such as oats.

Instead, feed high quality, low phosphorus protein such as cooked egg and food high in antioxidants such as fresh fruit. Omega 3 has a potent anti-inflammatory effect on the kidneys so oils such as flax seed oil can be beneficial in a kidney-friendly diet.

Consider Heart Health

Very conveniently, the nutritional requirements for heart conditions largely overlap with that of kidney disease. To support the heart and reduce the load on the cardiovascular system, low sodium and high omega 3 is the mainstay of a heart-healthy diet.

The Dreaded C-Word

Cancer, unless externally visible, often goes undiagnosed until the associated lethargy and weight loss are severe and cancer is likely at an advanced stage.

After many millennia of using rats for cancer research, we have gathered a milieu of evidence of the powerful anti-cancer properties of dietary anti-oxidants, specifically in rats. I explain specific anti-oxidants I’m more detail further down the article.

Joint Health

The single best thing you can do to keep your rat’s joints healthy, is to prevent them from becoming overweight. It is much easier to try and prevent joint problems than to try and treat it when the damage has already been done.

The second best thing you can do when your rat does not climb ladders and navigate multiple cage levels as he or she used to, is to add chondro-supportive supplements such as glucosamine and chondroitin to their diet. Glucosamine and chondroitin are both found in cartilage-rich food such as bone broth (rats love bone broth! Just remember to forego the salt or stock cubes or by a low-sodium version) and fish.

And here is another honorable mention for Omega 3 fatty acids: this is probably one of the most powerful researched natural anti-inflammatory compounds we know, so naturally, it will help with inflamed and sore joints.

Metabolic Efficiency

As rats start to age and become less active, their muscle mass and strength will also start to decline. This is where Carnitine supplementation comes in.

Carnitine is a naturally occurring amino acid found mostly in muscle and helps the body to break down fat as fuel. As a rat’s carnitine levels start to decline due to reduced muscle mass, and the body becomes less efficient at producing energy, carnitine works to help energy production. Read on for more details on carnitine later in the article.

How Much and How Often Should I Feed My Senior Rats?

The best is to feed according to trends or changes in their weight. Here are some general guidelines:

An adult rat should eat 15-20 grams of food per day or around 60 calories, divided into 2 – 3 meals. It is best to monitor your rat’s weight by weighing them on a kitchen scale on a weekly basis to check that they are not losing or gaining weight and then feed them accordingly. An adult female rat should weigh around 250 – 400 grams, and males should weigh around 300 – 600 grams.

Multiple research papers have shown that calorie restriction has a positive effect on longevity that can be compared to none other. I can not stress this enough: preventing your pet rat from becoming overweight is one of the best ways you, as rat owner, can help your rat live a longer, healthier life.

Preventing your pet rat from becoming overweight is one of the single most effective things a rat owner can do to help their rats live longer, healthier lives.

Have a look at this handy article by Dr. Pieter for more tips to prevent obesity in pet rats and how often they should be fed.

If you start to notice a decline in the appetite of your pet rat, I would urge you to take your rat for a check-up at your vet. In the overwhelming majority of cases, the earlier the disease is directed, the better the outcome of treatment. And I must add, rats are great at hiding illness, so if something feels off, rather be safe and get it checked out. Knowing your rat’s weight trends can be a very helpful tool in this regard.

What Supplements Do Senior Rats Need?

Omega 3 Fatty Acids

Think fish oil, cod liver oil, or flax seed, but avocado is a bit risky in my opinion. Firstly, avo pip and peel are a definite no-go for rats and it is toxic to nearly most domestic animal species. I generally advise rat owners to not feed anything to their rats that are toxic to other domestic animals such as dogs and cats.

I have yet to find a rat that enjoys the taste of fish oil or omega 3 soft gels. Luckily there are wonderful tasty omega 3 supplements for pets on the market. Dog and cat omega 3 chews or treats work well (I like this one by Zesty Paws) for rats as well. You can give half a treat per rat per day.

Anti-Oxidants such as Lipoic Acid

Lipoic Acid is a very potent antioxidant found in leafy green vegetables. A study done by Hagen et. al (1999) found that older rats that ate a diet rich in lipoic acid could figure out a maze and remember the correct route much quicker than rats that ate a standard rat ration.

If I can take you back to High School biology for a moment. Remember the infamous powerhouse of the cell, the mitochondria? Well, this potent piece of cellular machinery can sometimes produce free radicals and oxidants that damage DNA. This increases as the cell ages and oxidative damage to DNA is one of the known causes for cells to become cancerous.

The magic of anti-oxidants are that they prevent these types of oxidative damage and essentially helps the mitochondria to burn fuel more efficiently.

Vitamins such as A, E and C and grape seed oil are also note-worthy antioxidants. Vitamins A, E and C are abundant in foods such as berries or fresh vegetables. So, make sure to feed a portion of fresh food every day. A few rounds of carrots, baby corn, peas, strawberries and blueberries are great options.


Carnitine is another substance that helps the mitochondria and declines with age. This amino acid acts like a tiny railway to fast-track fatty acids (the building blocks of fats) into the mitochondria for energy production.

It is usually produced in the liver, brain, and kidneys and is beneficial in managing heart and kidney disease. It is important to note that specifically, L-Carnitine is the biologically active form of carnitine. So check the ingredient list of the pet supplement for specifically L-Carnitine or Acetyl-L-Carnitine as these to forms are the most effective.

Carnitine also helps maintain lean body mass as it makes it easier for the body to burn fat as fuel instead of breaking down an already declining muscle mass in a senior rat.

What Foods Should be Avoided When Feeding Senior Rats?

Avoid diets formulated for other small pet mammals diets such as rabbits, gerbil, and hamster diets. These species’ diets often contain a large amount of indigestible or poorly digestible grains because the digestive tracts of these species are very different compared to rats.

As mentioned previously, stay away from salty human food, sugary food and anything known to be toxic to dogs and cats (not everything is equally as toxic to rats, but this is generally a safe guideline).

Other ingredients to steer clear from, no matter what the age of your rat is:

  • Chocolate
  • Caffeine
  • Foods High in Salt (most processed human food)
  • Carbonated soft drinks
  • Green bananas or potatoes
  • Uncooked beans

Healthy Treats For Senior or Frail Rats

The bulk of your rat’s diet should consist of a high-quality rat food from a reputable brand such as Oxbow’s Adult Rat Food (Kaytee is another good brand to consider). Offering your rats other nutritious snacks is simply to supplement to the foundation built by a properly formulated rat food. Plus it’s fun for your rats and supplemental food items can have tremendous health benefits – you probably already know this because you are reading this article!

Healthy Whole Food Treats

  • Boiled or scrambled eggs
  • Berries – blueberries and strawberries are a favorite
  • Green vegetables such as baby spinach
  • Other vegetables such as peas, carrots and corn
  • Small amounts of nuts such as almonds

Supplements To Offer As Treats

This article has armed you with the knowledge on which type of ingredients to look out for in supplements and treats for your senior pet rat. If you know what to look for, it is not that hard to find. Remember that dog and cat supplements can also be given to rats, just in smaller amounts.

I can wholeheartedly recommend the following supplements for senior rats:

Final Thought

There is no disease called old age. Old age is simply associated with a higher likelihood of developing certain diseases. Luckily, there are many ways rat owners can use what they feed their rats to help stave off the dread of old age. I hope you can use the knowledge you gained from this article to help keep your senior rat happy and healthy for as long as possible.


  • Choi, S., Zhang, X. and Seo, J., 2012. Suppression of oxidative stress by grape seed supplementation in rats. Nutrition Research and Practice, 6(1), p.3. https://synapse.koreamed.org/articles/1051229
  • Erdogan, H., Fadillioglu, E., Ozgocmen, S., Sogut, S., Ozyurt, B., Akyol, O. and Ardicoglu, O., 2004. Effect of fish oil supplementation on plasma oxidant/antioxidant status in rats. Prostaglandins, Leukotrienes and Essential Fatty Acids, 71(3), pp.149-152. https://www.sciencedirect.com/science/article/abs/pii/S0952327804000432
  • HAGEN, T., INGERSOLL, R., LYKKESFELDT, J., LIU, J., WEHR, C., VINARSKY, V., BARTHOLOMEW, J. and AMES, B., 1999. ( R )‐α‐Lipoic acid‐supplemented old rats have improved mitochondrial function, decreased oxidative damage, and increased metabolic rate. The FASEB Journal, 13(2), pp.411-418. https://faseb.onlinelibrary.wiley.com/doi/full/10.1096/fasebj.13.2.411
  • Hagen, T., Liu, J., Lykkesfeldt, J., Wehr, C., Ingersoll, R., Vinarsky, V., Bartholomew, J. and Ames, B., 2002. Feeding acetyl-L-carnitine and lipoic acid to old rats significantly improves metabolic function while decreasing oxidative stress. Proceedings of the National Academy of Sciences, 99(4), pp.1870-1875. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC122286/
  • Palou, M., Sánchez, J., García-Carrizo, F., Palou, A. and Picó, C., 2015. Pectin supplementation in rats mitigates age-related impairment in insulin and leptin sensitivity independently of reducing food intake. Molecular Nutrition & Food Research, 59(10), pp.2022-2033. https://onlinelibrary.wiley.com/doi/abs/10.1002/mnfr.201500292
  • SUH, J., SHIGENO, E., MORROW, J., COX, J., ROCHA, A., FREI, B. and HAGEN, T., 2001. Oxidative stress in the aging rat heart is reversed by dietary supplementation with ( R )‐α‐lipoic acid. The FASEB Journal, 15(3), pp.700-706. https://faseb.onlinelibrary.wiley.com/doi/full/10.1096/fj.00-0176com

Dr. Annerien de Villiers

Dr. Annerien de Villiers graduated as a veterinarian from the University of Pretoria in 2018. She has since worked full-time in clinical practice tending to all kinds of companion animals in general practice. Serving the human-animal bond with care and compassion and making accurate information accessible to pet owners is at the heart of her driving force as a veterinarian.

Recent Posts