Posts tagged hyperthyroid

Food + Chemicals + Dust = Hyperthyroid Kitties?

A serious disease affecting cats’ thyroid glands has risen to epidemic proportions since the first cases were diagnosed in 1979. It is a worldwide phenomenon, though worse in the U.S. than other countries.

The disease itself, called hyperthyroidism (hyper = too much, thyroid = a hormone-making gland), is seen mostly in older cats age 10 or more. Thyroid hormone regulates the body’s basic metabolic rate. Too much of it is like drinking too much coffee—it speeds up every reaction in the body.

Symptoms of hyperthyroidism are related to excess thyroid hormone: excessive hunger, weight loss, restlessness, yowling, vomiting, diarrhea, and heart disease. However, about 20% of cats are “atypical” and do not show these symptoms. (Dogs also develop thyroid disease—but in the opposite direction. They are more prone to hypothyroidism; a deficiency of thyroid hormone.)

Many theories have been proposed to explain the dramatic rise in feline thyroid disease. Because it affects so many cats, the focus has been on widespread, environmental causes.

Studies have found several suspects in cat food:

  • One theory implicates the large excess of iodine found in many cat foods. Humans can develop hyperthyroid disease from too ingesting much iodine; might cats do the same? Iodine is difficult and expensive to test for; instead, pet food makers routinely add extra, just to make sure that minimums are met. But how much is too much? So far, nobody knows; and nobody is really looking.
  • Several studies found an increased likelihood of developing thyroid disease in cats who eat a lot of canned food. Specifically, they found a higher incidence of hyperthyroidism in cats that ate fish or “giblet” canned foods. “Giblet” is another name for organ meats commonly listed on pet food labels as “by-products.” Better-quality, natural cat foods do not contain by-products, although some include specific organ meats like liver.
  • Recent research suggests that the culprit may be a chemical (bisphenol A and similar compounds) found in can linings of pop-top cans that can leach out into the food and cause toxicity (the smaller the can, the more chemical exposure the food has). However, there are at least 25 different types of can linings, and the particular type used by a manufacture may change over time. It is difficult to know which foods may be affected, and to what degree. The FDA, however, has stated that the amount of chemicals that may leach into the food is unlikely to cause disease.

A new study that recently captured media attention suggests that fire-retardant chemicals known as PBDEs may be a factor in feline hyperthyroidism—even though the study itself clearly states “no association was detected between hyperthyroid cats and PBDE levels.” The authors note that PBDEs were introduced at about the same time hyperthyroidism was first described in cats. California was particularly aggressive in promoting these life-saving fabrics, which could explain why the veterinary school at U.C. Davis saw so many early cases of hyperthyroid disease in cats. Additionally, the rate of feline hyperthyroidism has roughly paralleled the use of PBDEs in other countries. This particular study looked at only 23 cats (less than half with hyperthyroid disease; and the case controls were not well-matched in age or gender.

The main route of exposure in cats was hypothesized to be the PBDEs contained in carpets, upholstery, and mattresses—and the dust mites that live in these fabrics. Electronic equipment, which attracts dust, is also a suspect. Since cats often sleep on carpets, sofas, chairs, mattresses, and nice warm TVs and stereos, their exposure could be high and prolonged. Subsequent grooming would then cause the cat to ingest a fairly large amount of dust. This may explain why hyperthyroidism is also more common in indoor cats.

Perhaps the most interesting wrinkle in this recent study is that PBDEs were also found in cat food. For two major types of PBDEs, high levels were found in canned food, especially fish- or seafood-based cat foods. However, high levels of other PBDEs were also found in dry cat food.

The double (or triple) whammy from PBDEs, can liner chemicals, and excess iodine may be too much for many cats to handle. However, outdoor cats who never eat canned food can also develop the disease—so other factors that haven’t yet been discovered are likely to be involved.

What can you do to minimize the risk for your cat? Well, it wouldn’t be smart to push your cat outdoors—the dangers outside are far worse, and most of them will kill your cat long before the age where she’s at risk for thyroid disease. Ripping out all your carpets and throwing away your furniture probably isn’t practical.

However, we also would not recommend feeding only dry food. There are many health risks for cats that eat too much dry food, including obesity, diabetes, arthritis, urinary tract disease, constipation, kidney disease, and inflammatory bowel disease. A variety of high-quality, natural foods—including at least 50% canned food—is your cat’s best bet for a long and healthy life.

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Thyroid Problems: Food + Chemicals + Dust = Sick Kitties?

Feline thyroid disease has risen to epidemic proportions since it was first diagnosed in 1979. It is a worldwide phenomenon, although it’s worse in the U.S. than other countries.

The disease itself, hyperthyroidism (hyper = too much, thyroid = a hormone-making gland) is seen mostly in older cats; usually in cats age 10 or more. Thyroid hormone regulates the body’s basic metabolic rate. Too much of it is a lot like drinking too much coffee—it speeds up every reaction in the body. Symptoms are typically related to this excess: excessive hunger, weight loss, restlessness, yowling, vomiting, diarrhea, and heart disease.

(Dogs also develop thyroid disease—but in the opposite direction. They are more prone to hypothyroidism; a deficiency of thyroid hormone.)

Many theories have been proposed to explain the dramatic rise in this new disease. Because it affects so many cats, the focus has been on widespread, environmental causes. Studies have found several suspects in cat food:

  • One theory implicates the large excess of iodine found in many cat foods. Humans can develop hyperthyroid disease from too ingesting much iodine; might cats do the same? Iodine is difficult and expensive to test for; instead, pet food makers routinely add plenty of extra, just to make sure that minimums are met. But how much is too much? So far, nobody knows; and nobody is really looking.
  • Several studies found an increased likelihood of developing thyroid disease in cats who eat a lot of canned food. Furthermore, there was more hyperthyroidism in cats that ate fish, liver, or “giblet” type canned foods. “Giblet” is another name for organ meats commonly listed on pet food labels as “by-products.” High quality, natural cat foods do not contain by-products.
  • Further research suggests that one factor may be a chemical (bisphenol A and similar compounds) found in the lining of pop-top cans that can leach out into the food and cause toxicity. However, there are at least 25 different types of can lining, and no  answer on which one(s) may be harmful. According to the FDA, the low levels of these chemicals found in some cat foods pose no health risk.

Recently, the media reported that fire-retardant chemicals known as PBDEs may be a factor in feline hyperthyroidism. The authors of a small study noted that PBDEs were introduced at about the same time hyperthyroidism was first diagnosed in cats. Additionally, the rate of feline hyperthyroidism has roughly paralleled the use of PBDEs in other countries.

The main route of exposure in cats is thought to be the PBDEs contained in carpets, upholstery, mattresses, and electronic equipment—and the dust mites that live in these fabrics. Since cats often sit and sleep on carpets, sofas, chairs, and mattresses, their exposure would naturally be high and prolonged. Normal grooming activity would also cause the cat to ingest a fairly large amount of dust. This may explain the increased risk of hyperthyroidism in indoor cats. However, although several cats in the study had high levels of PBDEs, the authors clearly state, “no association was detected between hyperthyroid cats and PBDE levels.”

Perhaps the most interesting bit of info to come from this recent study is that PBDEs were also found in cat food. For two major types of PBDEs, high levels were found in canned food, especially in fish- or seafood-based cat foods. High levels of other PBDEs were found in dry cat food.

However, many hyperthyroid cats have never eaten canned food, never gone outside, and have no exposure to any of the other potential “causes” of the disease. But because hyperthyroidism strikes older cats, it is likely that there are multiple factors that come into play throughout the cat’s life. There is no “final answer.”

What can you do to minimize the risk for your cat? Well, it wouldn’t be smart to push your cat outdoors—the dangers outside are far worse, and most of them will kill your cat long before the age of thyroid disease. Ripping out your carpets and throwing away your furniture probably isn’t practical.

Diet does seem to be one area where we can make a difference. However, it is not a good idea to feed only dry food. There are many common health issues associated with dry food: obesity, diabetes, urinary tract disease, constipation, kidney disease, and inflammatory bowel disease. A variety of high-quality, natural foods—including at least 50% canned or fresher food (not dry) —is your cat’s best bet for a long and healthy life.  For fresher foods without the can try dehydrated food such as Honest Kitchen Prowl , freeze dried such as Nature’s Variety Freeze Dried Diets, or frozen raw food for cats.

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