Keeping Perspective on Pottenger's Study

In recent years, poor Dr. Francis Marion Pottenger, Jr. has been maligned, and abused by people who have misinterpreted and prevaricated the results of his study with felines for their own biased agendas, such as book sales, and I think it is time more people recognized his real contribution to the world of nutrition in general, and to felines in particular, as well as correct the misconceptions put out there by those who reinvent the results of his study.

Back when Dr Pottenger set up the criteria for his study, little was known about feline nutrition, including the since established fact that cooked meat has less taurine than the requirements for feline health, first explored by Jacobson and Smith, 1968, a year after Pottenger's death in 1967.

If one is dealing with reality, this flaw in the ingredient list Pottenger created for his study eliminates all cooked meat formulas in his study, and leaves the other formulas all containing raw meat. From this point, of course, Pottenger does a wonderful job of proving that the ingredient list in any formula, PLUS the proportions, are what have importance when feeding any species as most of the raw meat formulas also failed as can be seen at the official Pottenger site listing study results.

You may note at the above Pottenger site, there were two major divisions in the study, one of which strictly compared equal formulas with one cooked, and one raw meat difference in ingredients. That study, as I mentioned, is flawed due to the lack of taurine supplementation and can't clearly define that processing method is an issue.

Of the remaining information, all under the heading of "Milk Study", ALL containing raw meat, ONLY ONE of five categories, (differing ingredients), were not considered "deficient". What this study proved was not a matter of raw vs. cooked, but of ingredient proportions, based upont the information on the site, and clearly shows that not only the right ingredients, but also the right proportions matter when addressing nutritional needs.

Aside from the taurine issue, our own sedentary house cats can't handle the fat content found in raw food diets as the caloric count is too high. Our choice is to pick rendered "meal", and in particular a feline appropriate source, which is chicken. Most people who do choose to feed raw chicken, do not request that the meat be "extra lean", which is what my boys would need in order not to end up overweight. Also, when one is running down an ingredient list for comparison, raw always has to have water content in the measurement, by default, which is why equal cuts of turkey breast (cooked #020), at nutritiondata.com contain 30.1% protein, and the same cut in raw (#148) form only contains 24.6% protein. This reduces the protein content of the raw meat based upon 100 gram servings, while calories are high.

When you add to the above facts the information one learns in Food Safety courses around bacteria, I am just not willing to subject my immune compromised, or healthy cats to the risk. The educated feline professionals on line suggest "searing" the chicken before grinding or serving for use. Have you seen the shape of a chicken piece? As there is no scientific evidence to suggest raw is better than cooked, I am happy with my choices, and my boys are healty.


How Protein is Measured

Protein is the one type of nutrient that has nitrogen added to the chemical composition. This study demondstrates how the protein content is calculated, which tells one nothing about the quality of protein sources, or what the amino acid makeup is, meaning whether it is, or isn't a complete protein. Along with this very antique Kjeldahl method developed in the late 1800's, there is the Dumas test that can extract ~2% more protein content from a product. There is a comparison of these two on this site.
There are new methods being explored, but they are not readily utilized as consumers are not demanding more proficient methods of measurement in pet foods. The latest accepted test is the NIR test, which tests for peptide bonds in protein that has been extracted from a source. Some of the more recent, cumbersome tests are described here.
Dry Matter Calculations:
Find the moisture percentage on the label (usually 70-80 for canned)
Subtract that from 100, (should be 20-30 for canned)
Now, move the decimal 2 places left (should be .20 to .30)
Use that number to divide into any other percentage on the label to get what is termed "Dry Matter Percentage" for that particular item. For instance, if your answer was .25, and the protein percentage was listed on the label as 10%, you would divide 10 by .25 and come up with 40, indicating that 40% of the dry matter in the food is actually protein content.

Many people have trouble understanding why I will pick a good dry food over a good canned food for weight reduction, so, to take this further, using top quality canned foods and top quality dry foods as an example with high muscle meat protein in both.

Canned Food Example = Fancy Feast varieties at 11% protein.

First you calculate the Dry matter percentages of the nutrients as shown above. Then you have the final percentage figures listed below, and what follows is the interpretation into caloric count of the food.

Canned food for 100 grams:
80% moisture = 80 grams of moisture leaving 20 grams of nutrition in 100 grams of canned food
50%, (dry matter calculation), of that 20 grams would be 10 grams of protein (40 calories)
22.7 %, (dry matter calculation), of the 20 grams would be 4.54 grams of fat. (40.86 calories)
That leaves about 5.46 grams left for carbohydrates and "ash" or 27.3% of the can's dry matter content. (21.84 calories)
Total amount of caloric content here is 102.7 calories.

Dry food for 100 grams:
10% moisture = 10 grams of moisture leaving 90 grams of nutrition in 100 grams of dry food.
44%, (dry matter calculation), of that 90 grams would be 39.6 grams of protein, (158.4 calories)
9.4%, (dry matter calculation), of that 90 grams would be 8.46 grams of fat, (76.14 calories)
That leaves about 41.94 grams of carbohydrates and "ash" content or 46.6 % of the dry matter content, (167.76 calories)
Total amount of caloric content here is 402.30 calories although Royal Canin is claiming 257 for this measure of their Indoor dry on the package.

According to the NRC, cats need an absolute minimum of 3.97 grams of protein per Kilogram of weight. If you start with a 16 pound cat you have about 7.25 Kilograms of cat to nurture before cutting back on calories. That requires approximately 30 grams of protein provided by the food you feed. This would require 2.8 cans (287.56 calories) of the cat food, or 3/4 of a cup of the dry food  (about 300 calories).
Other dry and canned foods are not equal to these calculations.  Most canned foods require more food to provide adequate protein in the diet, and opposite to that, most dry foods have higher caloric count due to fat replacing "carbs" or inappropriate ingredients, which happens with both canned and dry.
There would be about a 10 to15 calorie advantage to feeding the canned over the dry, however, we found that we didn't need more than half a cup of the dry food for our boy needing high protein. He started at 16 pounds before weight loss. The advantage to dry is that it can be left in small timed feeding portions. Everyone knows that "portion control" is what drops the weight as the stomach shrinks with time. While I have taken actual figures from the foods I recommend, there are few canned foods you can find that are as high as 11% protein on the guaranteed analysis, so that will easily take up the "15 calorie" difference to equate the provision of adequate protein. However, if you doubt what I say, you can follow the calculations above to come up with your own figures on this.


Protein and CRF

Some of the information around the issue of feeding cats with renal failure is either written in books that have copywrite, or the URL's keep changing. I will try to keep information on this site current.

First there is information written by Daniel P. Carey DVM and Leighann Daristotle DVM, PhD on the importance of protein for felines suffering CRF and demonstrating a concern about restriction of protein in the diet of a CRF patient. Unfortunately, Iams has removed their page from public access.

Then, Kenneth C. Bovée, DVM, MMedSc discusses the fact that there is no scientific basis for restricting good quality muscle meat protein in a cat facing renal failure, at least to the point of meeting the cat's nutritional needs.

Gregory Reinhart PhD's comments quoted from the Iam's Symposium papers in regard to dogs, who need less protein than cats. The same principles apply to cats. I should clarify, here, that Dr Reinhart has been financed by a variety of pet food companies, as are other researchers, and Iams only sponsored these specific symposiums, just as Purina did elsewhere, the same year, as you will see noted at the bottom of one or two of the above referenced papers.

There is also Finco et al who stated, "Results raise questions about the practice of restricting quantity of protein in the diet of cats with chronic renal failure, with the intention of ameliorating development of further renal damage," as part of their conclusion.

Another Note on Protein:

According to this information, written by David J. Polzin, DVM, PhD, Diplomate ACVIM, there are various reasons why your cat can have altered control, or lack of control, of glucose levels. You may note that reference is made to reduction of protein in the diet possibly causing the raised glucose levels.

And on Plant Based Oils:

Also, Scott A. Brown, VMD, PhD, Diplomate ACVIM, suggests trying to improve the Omega 3 fatty acid ratio with a cod liver oil capsule as the study suggests this may help. In a convoluted way the article points out, "However, cats have limited hepatic delta-6 desaturase activity and thus cannot effectively convert linoleic to arachidonic acid and both are considered essential dietary fatty acids in cats.18). In other words cats have "limited" ability to extract fatty acids from plant material, (not a feline appropriate source), so I would head for fish oils where you can, and find cat foods that are supplemented with Omega 3's. At the 28th Congress of WSAVA, Dr. Brown, echoes his theory in his speech. Information on this is echoed on our Petfood Pitfalls page under Flax Seed (Oils). Another study reflecting the absence of D6D activity in cats is here.


The good grains and vegetable content

Corn Gluten Meal as second or lower ingredient:
As I am continually providing information on this subject, I have decided it is best to record it here so that it is readily accessible at any time for those who care to have their facts straight.
  • Anyone with training in food chemistry will be able to tell you that the term "gluten" refers to the protein content of corn. The information is backed up on many sites online. The difficulty with corn gluten meal is that it doesn't contain all the amino acids needed by felines, so you definitely need to have muscle meat protein "meal" as a higher protein source than the corn. Remember that "meal" is dry weight and not mostly water.
  • At Ingredients 101, there is a breakdown of corn as a commercial ingredient sold for livestock feed. While the protein content there is estimated to be 60%, I have found higher percentages provided online by government inspected enterprises.
  • One often finds comments about corn gluten meal being "useless" to felines, however, the prestigious PubMed site shows a study regarding feline assimilation of corn gluten meal where it was found to be 2.5% less bioavailable than chicken meal. In that paragraph, on the third line, click on Table III to confirm the following figures:
    meat meal - 83.3%
    chicken meal - 80.2%
    corn gluten meal 77.7%
  • In the above study, in Table IV, the absorption and retention of nitrogen from those figures were slightly more realistic in representation, in that actual nitrogen retention with the remainder being excreted in either urine, or feces was:
    meat meal - 18.3 ± 4.4
    chicken meal - 13.1 ± 4.6
    corn gluten meal - 11.8 ± 7.3
  • In the above study, under "Diet", Table II also breaks down amino acid content of corn gluten meal as compared to meat meal and chicken meal. Corn gluten meal contained as much of the sulphur amino acids, (methionine and cystine), as the other two, whereas other grain and vegetables are lacking in these amino acids. The importance of this is in the development of struvite crystals. Sulphur amino acids are needed to provide an acid pH that will prevent crystal development.
  • Corn gluten is used as a germination retardent , which is used for sensationalism by those who have an agenda, that has nothing to do with corn gluten meal's capability of safely supplying nutrition to our companion animals. The safety of the ingredient is reflected in the fact that it cannot harm living organisms, and in fact, as it breaks down, becomes a high nitrogen fertilizer because of the protein content.
The next two products are discussed at a site that reflects some of the recent research done on fermentable fibres for felines done by Sunvold and Reinhart. You may notice in Table 6 that both acceptable fibre sources are moderately fermentable, and have low solubility. This article is a composite of other papers presented at different times to their peers.
Rice Bran:
Rice bran is the outside layer of the rice kernel, which contains the bran, and part of the rice germ. It is the part of the rice kernel that is removed to make brown rice. The first URL, and this one, take you to nutritional breakdowns of the product.
Beet Pulp:
Beet pulp is the other, more commonly used fermentable fibre with low solubility, and moderate fermantability, as recommended in the Reinhart and Sunvold paper presented to the 1996 Iams Symposium. It is the vegetable matter, which remains after sugar is extracted from sliced sugar beets.
Some interesting studies on this subject can be found here, here, and references are made in the National Research Council, (2006) book on Nutrient Requirements of Dogs and Cats Page 38 of these notes from the Iam's symposium states, "Fiber digestibility was greatest for cats consuming a diet containing beet pulp (a moderately fermentable fiber), a diet containing the highly fermentable blend of fibers and a diet containing a combination blend of fibers designed to provide moderate fermentation (beet pulp, rice bran, citrus pectin, and carob bean gum)"



For a number of years there have been questions regarding Moducare, suggesting that it is not appropriate for felines because of the alleged quantity of simple carbohydrate used as an anti caking agent, etc., so I am hoping to spend time providing a good list of reference material for those who have a sincere interest in using available resources for their companion animals. Some of the reference material will relate to AIDS studies as our own collection has been focused upon our dear FIV+ boy, Legolas. However, we are finding that Moducare does a very good job of maintaining our diabetic, Hamlet, who also suffered from asthma, previous to using this product. Moducare appears to be keeping this in check so that we don't need to resort to inhaled steroids, which would concern us more, as the residue from the steroids has to go somewhere, and so far there are no good scientific answers we find acceptable. You will notice that the company has a few studies listed at their site attached to the hypertext above.

One of the most comprehensive lists of abstracts and studies that I have run across is put out by Big Five Veterinary Pharmaceutical Company (Pty) Ltd.  **Note, this site seems to be down.  While hunting to reconnect I am finding that South Africa is developing a protectionism because some of their products have been patented by foreigners without benefit to the natives originally providing the use.  There are a number of papers cited on the actual Moducare site that I haven't yet rechecked but previously they were similar to the "Big Five" papers.

A good site with general information on the use of Moducare, including recommended dosage, and the need to use without animal fats is The Analyst site.

The use of these specific phytosterols in animals is discussed in VETERINARY CLINICS OF NORTH AMERICA: SMALL ANIMAL PRACTICE Volume 34, Issue 1: Nutraceuticals and Other Biologic Therapies References to research are found at such sources as PubMed: Modulation of immune response through nutraceutical interventions: implications for canine and feline health.

April 21, 2009

Recently I have had more opportunity to research subjects close to Moducare use and have run across the following information around its use in cats:
CONCLUSIONS: The results confirm the correlation between apoptosis and the other parameters noted during the previous study and allows a comparison with FIV- cats. Spontaneous CD4+ apoptosis possibly protects the FIV+ cat by reducing the number of virus producing cells. This phenomenon was enhanced in the group treated with the immune modulator.


Choosing Feline Food

  • When you are reading the ingredient list on a pet food product, and trying to assess the amount of muscle meat protein in the product, please remember that ingredients are listed by weight (reg #3), which means that whole meat is also measured by the moisture content, and quite often you will find that the grain or vegetable listed right below the meat is likely to be providing more of the protein content than is good for our carnivore felines. That first ingredient containing all the moisture will probably be the total "moisture" source as listed on the package, unless "broth", or other moisture sources are shown. When the protein source is listed as "meal" it is the muscle meat source without the moisture detracting from the measurement, or is listed as "gluten meal" in grains, which results in only a partially adequate protein source, lacking in vital amino acids.
  • Along with watching for water content placing a nutrient source in a high position on the ingredient list, also watch for the opposite in that pet food companies are notorious for splitting an ingredient such as listing "corn meal", and "corn" separately, where both of these are sources of carbohydrates you are trying to avoid. By splitting the single ingredient source into two, it will be listed lower, and look as though there is less of it in a product that possibly one of those muscle meat sources that are so full of water.
  • Contrary to what is commonly promoted on the net, how a food is processed does not turn it into a "grain" or magically make it a good source of protein. Native Americans can tell you that when their ancestors dried meat, it was still a protein, not a grain. A good source of nutrient information is the nutritiondata site.
  • Another good site to use as a learning tool is at Royal Canin US, where such articles as the clarification of my first statement about meat, and other labelling issues are presented. They have another page clarifying the digestive differences between species, and one that breaks down corn, (a grain), to clarify the complexities of grains and their structure, at "Corn and Corn Gluten Meal". While corn gluten meal doesn't have a complete range of the amino acids needed for feline nutritional health, studies have proven it to be bioavailable regarding nutrients it does supply.
  • For ingredients not found on nutritiondata.com, there is a site for feed ingredient breakdown at Ingredients101
  • If you rely on supermarket sources for pet foods, you are likely to be paying later in vet bills. However, leading sources, (eg Small Animal Clinical Nutrition), do suggest that about 10% of the diet can safely be treats and junk food, just as we do with human diets.
  • You will often find products that contain fruits and vegetables, with the claim "no grains". In actual fact, felines come from the desert marshes, where rice and corn helped to develop their digestive systems, and, according to scientific research, rice bran is the best source of fermentable fibre, (moderately fermentable), along with beet pulp, for companion animals. If you look closely at the equivalent measurements to the ingredients in the "no grains" products, you will find that they consistantly have higher simple carbohydrate ratings than the equivalent serving of corn or rice. This can easily be checked on USDA National Nutrient Database for Standard Reference, Release 18.

In the US, in particular, the term "nutritionist" has no regulating guidelines in most states, even for use with human nutritional information. This means that anyone can claim to be a "feline nutritionist" with impunity, and it is a case of caveat emptor, or "you get what you pay for". The person does not need to have any credible education behind the term, and usually doesn't have good scientifically based reference material backing up the important information they provide on their sites. You will usually notice a specific bias in the postings, toward one method of processing or another, when, in actual fact, if the ingredient is in the food, the processing doesn't make it good or bad, as you can easily discover by doing comparisons at NutritionData.com. Sometimes an ingredient will be slightly higher in one nutrient or another, based upon processing method, but this is not consistant with any method of processing, and the differences are not really enough to base a change in feeding practices. Learn to understand the ingredient lists and assess them by nutritional breakdown from the reliable sites above.

DRY MATTER CALCULATIONS, as kindly provided by Dr Craig Smith, DVM, of Tacoma:

  1. Find the moisture percentage on the label (usually 70-80 for canned, or around 10 for dry)
  2. Subtract that from 100, (should be 20-30, or 90)
  3. Now, move the decimal 2 places left (should be .20 to .30, or .90)
  4. Use that number to divide into any other percentage on the label to get what is termed Dry Matter Percentage for that particular item. For instance, if your answer was .25, and the protein percentage was listed on the label as 10%, you would divide 10 by .25 and come up with 40, indicating that 40% of the dry matter in the food is actually protein.....once the volume of water has been removed. As the dry matter amount is small in canned foods, you need to ensure you are providing enough to supply adequate nutrition for feline needs. That 40%, is 40% of the 20% or 30% of the can that is "dry" weight.

HAIRBALLS.........as a lot of us know, bulemia causes serious tooth decay in humans as the gastric juices continually pass by the teeth that are not designed to handle hydrochloric acid from the stomach. It is again assumption on my part that hairballs in cats can also create the same issues, with degraded dental hygiene. Our solution to this is to shave the cats that are prone to hairballs when weather warms up. Not only do we not suffer the mess of hairball on the floor; our boys love the freedom of shorter hair and become more active. This year Legolas's fur has grown back too quickly and he is complaining and cranky as the warmer weather stays longer than usual.

While the Iams Symposium papers are not available online, there are other workshops and symposiums provided here. They make an interesting read if you have time.

On your pet food labels, those items enclosed in brackets after a nutrient source are listed by law, as the ingredients that could possibly cause allergic, or intolerant reactions in some pets. Pay attention for the health and safety of your pet.

MSG issues are being addressed at the "Truth in Labelling" site. You may wish to do further reading with a very interesting book byRussell L. Blaylock, M.D., called "Excitotoxins: The Taste that Kills". I guarantee this book will have you reading through the ingredient lists for your own food much more closely, too. If the outline in the previous URL 'excites' you, the book is available through Amazon.com.

Specific pet food ingredient concerns are addressed here.

May all your pet food choices be made based upon education and reliable information, backed by science.