Better life for your hamster with better food

Two years ago, I became interested in health and nutrition. After gaining some basic knowledge of nutrition, I wanted to find an optimal (or at least better) diet for my pets. I still feed them with hamster mixes I choose carefully, but I also add nutritious, organic seeds, nuts and almonds, depending on each hamster’s condition and needs. Besides that, I feed them fresh food, which is optimal for their bodies’ metabolism, digestion and nutrient intake.
The purpose of this article is not to repeat the basics of hamster feeding, which most hamster owners are probably already familiar with, but to approach the subject from a new perspective. I don’t want to upset anyone by making them feel like they are bad hamster owners. That is not my objective, and I apologize if this article hurts anyone’s feelings. I’m just passing on information I learned from books such as “Nutrient Requirements of the Laboratory Animals”, “Laboratory Hamsters” and from numerous medicine releases.
Remember, good judgment comes from experience and experience comes from bad judgment.

A suitable diet

In the wild, a hamster’s diet isn’t nearly as balanced as in captivity. A wild hamster feeds with plants/plant-parts, seeds and insects. Still, there are often so many unexplained diseases or even deaths among pet hamsters. Symptoms usually indicate hypersensitive reactions, nutrient deficiencies or excess intake.
Although a Syrian hamster is omnivorous, sometimes I can’t help thinking people misunderstand the meaning of the word “omnivore”. Yes, hamsters eat both veggies and animal products but that doesn’t mean they can eat *anything* in order to maintain their health. For example, a human’s food doesn’t belong in a hamster’s diet, because their digestive system is more sensitive.
By “human foods”, I mean processed food products full of additives, colourants and preservatives, which might have unknown effects in the long term. Even though many people agree that salty, sugared or spiced foods are bad for hamsters, sugar-free (replaced with other sweetener), low salt and low fat factory-made products also aren’t suitable. Even if the hamster survives after eating that kind of food, it might reduce his life expectancy, cause irksome or even serious symptoms, such as diarrhea, bad hair condition, baldness, hyperactivity and heart conditions.
Humans’ bodies have had more time to become used to the foods we have nowadays. For example, the digestive systems of people who lived in northern countries mutated to tolerate lactose better than other people’s. Pet syrian hamsters haven’t changed much from their wild fellow creatures, apart from their color and minor differences between their sizes. Their nutritional needs, circadian rhythm and typical behavior for their species have remained the same. This is why I try to feed my hamsters foods without synthetic additives, and that are optimal for their health.

The food matters

I’ve seen “But my hamster likes it!” as an argument when discussing unhealthy foods. Many hamster owners may already be aware that some hamsters aren’t picky about their food. They eat their babies and even nesting wool, along with other harmful stuff! Just because he likes it doesn’t make it healthy.
A balanced, healthy and natural diet for hamsters boosts their immune system, therefore reducing the risk of getting sick due to nutrient deficiencies or other diseases. Unfortunately, people look elsewhere when trying to find the cause for the symptoms, because the impact of a diet on a hamster’s health is easy to forget, especially when you’re responsible for it. Please note that I am not suggesting that anyone attempt to medicate their hamsters with food though. Always consult a veterinarian, as a proper diet helps with preventive care.


Hamsters are used in laboratories to research the effects of specific nutrients and the optimal amount for them by causing deficiencies and overdosing. Although we and hamsters have copulative feature (omnivorous), our systems are very different, like our needs. As mentioned earlier, I tried to find out which nutrients are important and why. For this task, I used the books “Laboratory hamsters” (American College of Laboratory Animal Medicine Series) and “Nutrient Requirements of Laboratory Animals”. Because none of them mentioned *all* the effects of different nutrients, I mainly listed the symptoms (or lack of them) of all markable nutrients.
A brief explanation of two terms that will appear: Macronutrients are nutrients consumed in large quantities, like carbohydrates, proteins and fats. Micronutrients or microminerals are required in small quantities. These include vitamins and dietary minerals.

Carbohydrates, fats and proteins

Fats are important for healthy cell function and maintaining healthy skin and hair. They also assist in the nervous system, adjusting hormone metabolism and growth. There’s no evidence of the optimal amount of fat in a hamster’s diet, but 4-20 % in their food has shown good results. It depends on the hamster though, as they too have varying fat metabolism. An excessive amount of fat causes obesity and exposes hamsters to hypertriglyceridemia, which denotes high blood levels of abundant fatty molecules in most organisms. Symptoms associated with hypertriglyceridemia are white appearance of the retina and small lumps (sometimes itchy) in the skin.
In large amounts, animal fats may cause convulsions and increased mortality. Fat-free diets decreases growth in young hamsters and effects on gallstone formation.

Essential Fatty Acids

The requirement for ω-6 fatty acids has not been determined for hamsters but deficiencies result in a loss of hair, scaly skin and ear-wax.
No studies are available on the distribution of ω-3 fatty acids in hamster tissues or on the development of ω-3 fatty acid deficiency.
Carbohydrates provides the energy for organisms, which is used for the metabolism of other macronutrients. Carbohydrates are divided into sugars (e.g. glucose, fructose, lactose – many typical sugars end with “-ose”), starch and fiber. In a hamster’s diet, they are in fruits, cereals, nuts and seeds. Excessive amounts of fructose and lactose can increase mortality however. Also, it has been observed that “wet tail” can be prevented with rice flour or fiber.
Proteins are large molecules built from small units known as amino acids. They are part of tissues, cells and they strengthen the bones. There are two types of dietary proteins: animal proteins and plant proteins. The only difference between plant proteins and animal proteins is growth. In studies, hamsters fed with animal protein obtained a bit more weight than a group fed with plant protein. Ergo, the animal protein isn’t necessary for an adult hamster’s health, only the other important nutrients in animal products matter.
There isn’t a requirement for the amount of protein to support reproduction, but 18 percent protein is thought to meet the amino acid needs for reproduction in hamsters.
High protein intake leads to nephrosis. Casein (“caseus” in Latin, meaning cheese) is the name for the protein in mammalian milk, and in studies, it increased cholesterol and triglyceride levels in hamsters, caused amyloidosis and resulted in gallstone formation.


Calcium and Phosphorus
6,0 g calcium/kg and 3,5 grams of phosphorus/kg fed to a hamster is essential for normal bone formation. The signs of deficiency are dental caries and rickets.

Trace minerals

Iodine, molybdenum and selenium are essential for normal growth. A sign of iodine deficiency is enlarged thyroids. Iodine excess may cause accumulation of colloid.
Mild iron deficiency causes anemia, and low iron-diet during pregnancy can result in prenatal mortality and low maternal weight gain.
Copper deficiency causes hair depigmentation.


A hamster fed with balanced diet won’t need extra vitamins added to the hamster’s water bottle. Often “added” vitamins are synthetic, and they behave differently in the hamster’s digestion. A hamster often benefits more from natural vitamins. Some fat-soluble vitamins may be toxic, except vitamin D. Water-soluble vitamins usually flush out in the urine.

Fat-soluble vitamins

Vitamin A-deficient hamsters developed abnormally and had coarse and sparse hair, xerophthalmia, hemorrhages, weight loss and keratinized stratified tracheal lining. Also vitamin A-deficient hamsters formed stomach ulcers after 7 months of a vitamin A-free diet. Hamsters with high vitamin A intake (400,000 IU) developed liver pathology and died within 42-91 days.
Vitamin D deficiency may cause rickets to hamsters. No published reports on vitamin D deficiency or toxicity were found.
Vitamin E deficiency causes hamsters to develop testicular degeneration, decreased growth, muscular dystrophy and necrosis of central nervous system of fetal hamsters.
Vitamin K deficient hamsters have depressed growth rate, hemorrhages in muscles and subcutaneous tissue.

Water-soluble vitamins

Thiamin is necessary for growth, a deficiency may cause polyneuritis.
Riboflavin deficiency causes diarrhea, dermatitis, alopecia, reduced growth and stupor.
Niacin deficiency causes alopecia, rough coat and even death in the long term.
Pantothetic acid deficiency causes weight loss, porphyrin secretion and death.
Pyridoxine deficiency causes weight loss, poor growth, anorexia, hair loss, achromotrichia and increased urinary excretion of xanthuremic acid.
Biotin deficiency causes dull rough coats, encrusted eyes, depigmented hair and jerky movements.
Vitamin B12 deficiency causes increased urinary excretion of metabolites.
Folic acid deficiency causes anemia and reduction in blood and liver folates, which is more severe for females.

Other nutrients

Choline deficiency causes poor appetite, reduced growth and fatty livers.
Fiber deficiency together with high concentrations of purified sugars result in high mortality. The substitution of cornstarch for glucose or addition of 12-20 percent alfalfa to diets increased survival.
Ascorbic acid isn’t necessary for a hamster, however hamsters supplemented with ascorbic acid grew slightly faster than a group without it.
Myo-inositol isn’t required for growth, but is necessary for reproduction. The deficiency of myo-inositol may cause fur loss.

Nutrients in foods

I’m not suggesting that people *must* make their own seed mixes. I recommend checking what hamster breeders or experienced hamster owners recommend for seed mixes, and combine the good ones. You can also add high quality seeds, nuts and dried herbs to make your hamster mix even healthier.
It is a good idea to check the ingredients of each mix. If you find ingredients that look suspicious, contact the manufacturer to ask what they are, and if they use any colourants and/or additives in their brand. If they do, ask what they use. If you are not familiar with it, you can find out more information by searching online.
Please note: If you’re changing your hamster’s diet, do it slowly! Changing it too quickly can upset his stomach. If you’re adding a certain food into his diet, start with small amounts first, and then increase it over time. If you’re replacing a hamster mix with a different brand, blend some of the new mix with the old mix, gradually increasing the amount each day.
There are many nutritious fresh foods, and I haven’t probably listed them all. I used the Finnish Food Composition Database for the list, but there are other food composition websites in different countries. Links to them can be found here.


Sources for fat: nuts, sweet almonds, flax seeds, sunflower seeds, coconut oil and corn oil.
Sources for ω-6 fatty acids: Walnuts, sunflower seeds, sesame seeds, peanuts, cashews, sweet almonds, hemp seed.


Sources for protein: eggs, hemp seeds, cashew, sesame seeds, sunflower seeds, sweet almonds, soy, beans, turkey, broiler, tuna.
Macrominerals & Trace minerals
Sources for calcium: basil, sesame seeds, spirulina, hemp seeds.
Sources for phosphorus: wheat brans, wheat germs, sesame seeds, hemp seeds, spirulina, sunflower seeds, flax seeds.
Sources for iodine: spirulina, hemp seeds, wheat, oat.
Sources for selenium: sunflower seeds, sesame seeds, walnuts, rice.
Sources for iron: hemp seeds, basil, spirulina, wheat brans, sesame seeds, cashews.
Sources for molybdenum: buckwheat, barley, sunflower seeds, wheat germs, green vegetables.


Sources for vitamin A: rose hips, kale, sweet potato, carrot, spinach, spirulina.
Sources for vitamin D: eel, zander, salmon, common white fish, river lamprey, chanterelles.
Sources for vitamin E: hemp seeds, sunflower seeds, sweet almonds, wheat germs, hazel nuts, peanuts, basil.
Sources for vitamin K: basil, kale, spinach, nettle, carrot, spirulina, broccoli.
Sources for thiamin: spirulina, sunflower seeds, wheat germs, buckwheat, flax seeds.
Sources for riboflavin: spirulina, sweet almonds, wheat germs, kale, tomato, basil.
Sources for niacin: wheat brans, peanuts, carrot, basil, rice.
Sources for pantoteic acid: eggs, vegetables, legume vegetables.
Sources for pyridoxine: basil, corn, wheat brans, millet, sesame seeds.
Sources for biotin: oat, peas, eggs.
Sources for folic acid: basil, cauliflower, wheat brans, carrot, kale, broccoli, asparagus.
Sources for vitamin B12: herring, eggs, rainbow trout.

Other nutrients

Sources for fiber: basil, flax seeds, carrot, hazel nuts.
Sources for myo-inositol: banana, rice, oatmeal, vegetables, wheat germs, nuts.
Sources for ascorbic acid: rose hips, bell pepper, nettle, broccoli, strawberries, blueberries, hemp seeds.
Sources for choline: egg yolk, potatoes, cauliflower, peanuts, oats, barley, flax seeds, banana, tomatoes, sesame seeds.

Food additives

There have been concerns about the effects of preservatives and food additives, especially synthetic additives. The safety of food additives is measured with ADI (Acceptable Daily Intake) and the ADI is considered a safe intake level for a healthy *human* adult.
Food products designed for humans aren’t meant for animals, so we can’t be sure if they are safe for them because of their differing organisms. At worst, they could be too much for hamster’s system and lead to an illness or poisoning, and you won’t necessarily notice the symptoms right after giving the toxic food. At best, a hamster will only get an allergic reaction or not react at all.
Fructose, also known as fruit sugar, is a natural sugar which can be found in many foods, usually in fruits. It has been separated and used as a substitute for sucrose to sweeten certain foods. In studies, healthy, non-diabetic hamsters were fed a high-fructose diet, which resulted in insulin resistance and hepatic lipoprotein overproduction.
Fructose levels in fruits aren’t nearly as high as in baby foods, but in organic baby foods there isn’t added fructose, only smashed fruits and berries.
There are often a lot of synthetic additives in dog and cat foods. Some of them are forbidden from human foods, but are allowed in pet foods, such as butylated hydroxyanisole (E320) and butylated hydroxytoluene (E321). BHA is a carcinogen, and BHT may damage lungs. They both are used as preservatives, and even the European Parliament has admitted they both are harmful for health.
Preservatives and additives aren’t necessarily mentioned in labels, so in order to find out what ingredients are used in pet foods, it is best to contact the manufacturer. Their answer may be “All ingredients used in are approved by ” at first. If this happens, politely but firmly request a list of ingredients. At best, the list will be short and include harmless ingredients.
Dog and cat foods are commonly used to provide animal protein, which is odd. There are many better options, such as dried meat, fish or insects. Regardless, if you wish to feed animal products to your hamster, please use products with a national or third party organic certification if possible.


  • Nutrient Requirements of Laboratory Animals
  • Laboratory hamsters
  • The Hypocholesterolemic Effect of Dietary Soybean Protein vs. Casein in Hamsters Fed Cholesterol Free or Cholesterol Enriched Semipurified Diets: A.H.M. Terpstra, J. C. Holmes ja R. J. Nicolosi
  • Evira
  • Intestinal Lipoprotein Overproduction, a Newly Recognized Component of Insulin Resistance, Is Ameliorated by the Insulin Sensitizer Rosiglitazone: Studies in the Fructose Fed Syrian Golden Hamster: Gary F. Lewis, Kristine Uffelman, Mark Naples, Linda Szeto, Mehran Haidari, ja Khosrow Adeli
  • Chemoprevention of cancer: phenolic antioxidants (BHT, BHA)
  • Euroopan Parlamentti – Tarkistus 9 1 C ARTIKLA
  • Dietary Protein Effects on Gallstone Formation: David M. Klurfeld, Maxine M. Weber ja David Kritchevsky

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