Research Roundup

Research Roundup 15 BPA

Watch out for BPA
Nancy Scanlan, DVM

What is “BPA”? Most of you probably know bisphenol A (BPA) is a chemical increasingly used in plastics, and in linings of cans used for food, including dog food. It is also present in the paper of thermal printers and copied items, and in fire retardant chemicals used in rugs and draperies. 

Originally there was not much concern about it, since the amounts present in the blood and urine of human patients was below the safe level set by FDA, and short term studies in mice did not show any obvious problems. But then scientists started noticing that BPA makes permanent changes in our DNA, often by methylation of specific genes. Not only that – the changes can be inherited. Some reproductive problems started showing up in mice also, at the low dose that was supposed to be safe.

BPA is measurable in the blood and urine of children, and there is some question about what this might be doing to their bodies, and what that will mean for their own children. BPA is found in the blood and urine of humans worldwide. 

BPA has been associated with thyroid problems, obesity, heart problems, arteries going to the heart, and reproductive problems in humans. Similar findings have been reported for fish, sheep, dogs, and cats. BPA crosses the placental barrier and is present in the developing fetus; lambs born to mothers exposed while they were pregnant were hypothyroid. BPA has been linked with hyperthyroidism in cats.

BPA is found in the linings of cans of dog food and cat food, and pets eating those foods have elevated amounts of BPA. With canned items, there is more BPA in the solids than in liquids, so pouring off the liquid does not offer much protection. BPA is also found in plastic toys, and leaches out when dogs chew them, especially when lots of saliva is produced.

BPA is found in plastic containers as well as in can liners. Look for “BPA free” plastic bottles if you buy moist foods or liquids in plastic containers. Glass is BPA free, but the liner on the lid might have BPA. For a list of human foods that are sold in BPA free cans, see https://bpafreecannedfood.wordpress.com/bpa-free-canned-food-brands/

For pet foods, it is harder. The problem is in canned foods, not kibble in bags. Smaller 3 and 5.5 oz cans are generally BPA free, but it can be difficult for a company to find large cans that are BPA free. Trader Joes says all their pet foods are BPA free. It has been reported that Halo, maker of Spots Stew, is seeking sources of BPA free cans for all their foods. 

In a survey done 6 years ago, the following companies claim their pet foods are in BPA-free cans:

Blue Buffalo
Chicken Soup

Even the AVMA is concerned about BPA in dogfood cans. This week they noted reports from a study at the University of Missouri about the amount absorbed by dogs when eating food from cans with liners containing BPA. If you see a can with a white plastic lining, that can is releasing BPA into the food. 

So be diligent about buying human food in the right kind of cans, or use fresh or frozen instead. Support the companies who sell BPA-free foods. Watch for other sources of BPA and minimize exposure to those. And watch out for sources you might not be aware of: Those shiny receipts you receive from cash registers when you finish shopping are also a source of BPA.

Research Roundup 14 - Best Balance of Probiotics

How do you create the best balance of intestinal bacteria for optimum health?

Mammals need bacteria in their digestive tract. If too many are killed by antibiotics, diarrhea occurs. If an animal or person has diarrhea for too long, changes happen in the lining of the intestines, types of bacteria change, and the place where they live changes. The longer that this happens, the more permanent the change, and the harder it is to get it back.

The proper types of bacteria can help prevent some types of cancer, help decrease effects of some diseases such as kidney disease, and improve the immune system. Different bacteria do different things, and they do not all eat the same thing. So for best health it is better to have lots of different bacteria. To support them, it is good to have a diet with variation, to feed all these different types.

Intestinal bacteria can produce substances that have bad effects on the body. Trimethylamine, from bacteria in humans processing a diet high in conventional meat, eggs, and poultry, is absorbed and changed to a form that increases arteriosclerosis. However, the Mediterranean diet foods including balsamic vinegar, cold-pressed extra virgin olive oil, red wine, and grapeseed oil, as well as goat milk, goat meat, and eggs from chickens that graze on weeds daily, contain inhibitors of TMA production. I would not advise feeding your dog or cat red wine, but some of these other ingredients can be beneficial, and it is wise to use grass-fed and finished meat as well as pasture-raised poultry.

Bacteria in the intestines feed themselves by breaking down substances that intestinal enzymes can’t handle. They can also be increased or decreased by vitamins, minerals, and other nutritional substances in the body. For humans it has been shown that if you have a variety of different foods instead of sticking with one favorite fruit, one or two favorite vegetables, etc., you will support a lot more beneficial bacteria. This has not been officially studied in animals, but we have often seen that dogs which have chronic, long-term problems with diarrhea, or skin conditions, or other chronic disease will often do much better when changed from basic dogfood from the store, to a homemade diet. In addition, when experimental mice are fed a “Western type” diet (high fat, high sugar) instead of their basic mouse chow diet, all degenerative changes have been, in the past, linked to the fat and sugar of that diet. But the diet has limited, simple ingredients, such as casein, cornstarch, sugar, and lard, compared to the chow diet which has more natural ingredients such as whole wheat, dehulled soybean meal, ground corn, animal fat and condensed whey. So at least part of the effects seen are conceivably from a more varied, more natural diet.

Wolves have a more varied diet than most people realize. Besides large herbivores (elk, caribou, deer, etc.) a regular part of their diet (not just when starving in winter) has been seen to include: seals, beavers, salmon, grey langurs in Nepal and hamadryas baboons in Saudi Arabia, marmots, hares, badgers, foxes, weasels, ground squirrels, mice, hamsters, voles and other rodents, as well as insectivores, waterfowl and their eggs, lizards, snakes, frogs, rarely toads and large insects (especially grasshoppers) and earthworms as available.  They also eat, in season, the berries of mountain ash, lily of the valley, bilberries, blueberries and cowberry, apples, pears and melons. Coyotes in my area also eat blackberries and manzanita berries, so I suspect wolves would also, if they were here in northern California. You can vary a dog’s diet a lot more than most people realize.

Humans use less than 1/1000 of known edible plants in their diet. The Food and Agricultural Organization of the United Nations has shown that 75 percent of genetic diversity has been lost in the plants that they do eat. 6 heritage breeds of livestock are lost each month, as general agriculture chooses species that grow the fastest or product the most eggs or milk, and tolerate high density crowding as they grow. They grow fruits and vegetables which ship well and take longer before they spoil. (Tomatoes are famous for this, often not resembling anything like you can grow or get at a farmer’s market.) 75% of the world’s food is generated from12 plant species and 5 animal species. So one part of improving intestinal health is to use some of the less common grains (such as quinoa), fruits, and vegetables. These can be found in farmers’ markets and health food stores, and if you have space to grow some of your own (even just in a hanging pot in your patio), there are heritage seed companies which specialize in hard-to-find varieties which often taste better but do not ship well.

So the first step in creating a better home for your own bacteria is to increase the variety of the fruits and vegetables you use. If you cook with bell peppers, try red, orange, and yellow ones, for example. Try other sweet peppers also. 

A second problem is with plant pesticides, fungicides, and weedkillers, used regularly on commercial crops. Residual amounts on feeds may affect intestinal bacteria. They also decrease or eliminate a plant’s need to produce phytoalexins, which help the plant cope with these problems. Phytoalexins provide nutrients for beneficial intestinal bacteria. To avoid the residual pesticides, wash and peel conventionally grown fruits and vegetables. To get maximum phytoalexin content, buy organic fruits and vegetables.

Prepared foods, especially dietetic food for people looking for a way to lose weight, may have substances such as oligosaccharides that the wrong (not beneficial) intestinal bacteria can process and use to increase their numbers. Carrageenan, a natural type of thickener, has turned out to be bad for you and your bacteria. Even dietary emulsifiers decrease the numbers of species of intestinal bacteria and can contribute to colitis. Nitrites, found in cured foods like hot dogs, bacon, and ham, cause abnormalities in the wall of the large intestines. Avoid prepared food (even “natural” foods) that have nitrites, carrageenan, or too many ingredients that are not whole foods and that have not been shown to be beneficial.

Secondary bile acids are produced by intestinal bacteria from bile. It has been shown that the more different types of secondary bile acids, the healthier the intestinal wall. To increase the types, use several classes of fats (saturated butter, monounsaturated olive oil, omega 3 fish or algae oil, polyunsaturated canola oil).

There is an increasing focus on vitamin D for humans for many benefits. It is possible, maybe even probable, that the minimum requirement for humans has been set too low. Vitamin D defi 

Different types of fiber support different populations of beneficial bacteria. Although fiber is often classified as “soluble” or “insoluble”, there are a lot of fibers which are in various stages in between, from almost soluble, to half and half, to almost insoluble. Different plants have different fibers along this spectrum. So, once again, the answer is multiple fiber types (if you are going to add fiber such as wheat bran, oat bran, canned pumpkin, or apple pectin), or multiple food types.

If you or your pet have had a restricted diet of the same old favorite foods or the same old pet food day after day, do not suddenly change to something different every day. That is an ideal way to create diarrhea. Adding small amounts of new foods gradually to the diet works best to gradually increase the bacteria which have been wasting away because they weren’t being fed. Probiotics can provide additional bacteria, but they can also upset the current balance. In general, there is good research support for Saccharomyces boulardii and also for a combination of Lactobacillus acidophilus plus Lactobacillus casei plus Lactobacillus rhamnosus being helpful in decreasing the number of harmful bacteria in the intestines of people. 

The final lesson: Prebiotics, probiotics, multiple types of fruits, vegetables, fats, and proteins support the healthiest types of bacteria in the intestines of humans and animals. Nitrites (cured foods), carrageenan, and “sugar alcohols” such as erythritol, glycerol, isomalt, lactitol, maltitol, mannitol, sorbitol, xylitol, and hydrogenated starch hydrolysates can cause problems from their breakdown products.

Go slowly in the introduction of new items, especially for those previously on limited diets, or any animal that seems to be sensitive to dietary changes. Keep the basic diet balanced but do not hesitate to introduce new foods in small amounts. Don’t worry if your dog likes earthworms – those are a part of Chinese medicine and he may be craving something that he needs. Grasshoppers may be a little problematic if your neighborhood uses a lot of pesticides, but otherwise they are just fine for any dog or cat who wants to try them. If you have settled into the same old rut for food, be adventurous and try something ethnic. And that does not mean Taco Bell!

(To see the references, see our HOPE newsletter.)

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