April 21, 2013

When You Cut Carbs, Don't Raise Phosphate Levels

Recently I've been reading up on the role of phosphates in heart disease, and what I am learning has some troubling implications for people who eat low carb diets. I already knew that people who have been diagnosed with kidney disease must avoid phosphates, as they can further damage the kideny's filtration units. I'd also discovered, and blogged about, the fact that and a person's lifetime intake of the phosphates present in brown-colored sodas, both diet and regular, have been found to correlate with their likelihood of developing kidney disease. (Details HERE)

But until recently, I had not realized that blood levels of phosphate that fall within the upper part of the supposedly normal range range on lab tests correlate with a higher likelihood of developing the calcified arteries that represent heart disease.

This is true even in populations of young, supposedly healthy people.

There are many studies linking phosphate consumption to poorer health outcomes. But most striking was this study published by researchers involved in the Framingham Offspring Study. They followed 3,015  young, healthy people for 15 years found that those with higher levels of phosphorus in their blood at the beginning of the study were more likely to have greater amounts of calcification in their arteries at the end of the study.

The researchers conclude, "... higher serum phosphorus levels, even within the normal range, may be a risk factor for coronary artery atherosclerosis in healthy young adults."

So where do these high levels of blood phosphorus come from? The answer is complex. Phosphorus is a normal part of the human diet. We need it for our bones and to regulate various physiological processes. Phosphorus occurs naturally in meat and many other foods we eat, which is where we get them. But it is likely that the damagingly high levels of phosphorus that make their way into our bloodstream and damage our arteries are not coming from the  meats and dairy we consume, but from surprisingly large amount of phosphorus-containing additives--usually phosphates--that are added to processed foods as a flavoring agent or preservative.

Added phosphates are found in many processed and restaurant foods. They are added to brown-colored sodas like Coke and Pepsi, and increasingly often to bottled ice tea. You will also find phosphates in most cold cuts, processed cheeses, and all rotisserie meats, including the ones sold as "all natural." There is phosphate added to half and half. They may even be found in supplements.

Phosphates are found in many of the meats you buy from the Meat department at your supermarket. Whole  and parted out turkeys and many chickens have labels that tell you they have been "enhanced" with solutions supposedly added to improve flavor. These solutions almost always contain sodium phosphate. (You can see a discussion of these enhanced meats HERE.) Phosphates are likely to be in prepackaged hamburger, but they may also be in pork products that were cut by the butcher. The only way to find out is to ask the butcher if the pork was enhanced with a solution.

While food labels may list phosphates in the list of ingredients there is no requirement that manufacturers list them, so phosphates are often omitted from labels. (Details HERE) Even worse, even when phosphate appear on a label, you have no idea how much phosphorus has been added. So unlike the situation with sodium, you can't track your phosphorus intake and keep it to a safe level. For that matter, it isn't even clear what the safe level is.

People with kidney disease are told to keep their phosphorus levels between 800 to 1,000 mg/day, though of course, doing this is virtually impossible since it is unknown how much phosphorus is in the many prepared foods they eat. But at least their blood phosphorus levels are measured, so they have some hint as to how they are doing.

But phosphorus levels are not tested as part of the standard suite of blood tests given to people with diabetes, so we have no way of knowing how high our blood phosphorus levels might be. Unfortunately, if you are eating a low carb diet, they may be higher than you realize.

When you eat out, you are almost guaranteed to be eating phosphates. Assume it is in all the chicken you order.  But the phosphates aren't just in the meat. McDonald's nutritional information (an oxymoron?) discloses that there are phosphates not only in all their chicken offerings--often two or three different kinds of phosphates--but also in their American Cheese, bacon, bacon bits, and Buttermilk Ranch Sauce.

But at least  McDonalds is honest enough to provide a complete listing of their ingredients online. Many fast food companies do not. Instead, they only provide the information required to be on the nutritional label, which does NOT disclose the presence or quantity of phosphates.

So what is a person to do? 

Phosphates may be posing a huge problem for all people with diabetes, firstly because so many people with Type 2 already have early kidney disease at the time they are diagnosed, and secondly because so many foods  we consider safe to eat because they don't raise blood sugar when we eat them may contain phosphates that can damage our vascular systems over time. 

Here are some steps you can take to limit the damage. The most important is this:


Once you become aware that phosphates are something you want to avoid, you may be shocked at how common they are in many foods that you have been thinking of as healthy.

After you become aware that our food supply is full of these questionable additives you can do the following:

1. Avoid drinking brown-colored diet sodas and bottled iced teas. Coke, Pepsi and Dr. Pepper usually contain phosphates.

2. Read the labels on everything you buy and if you have a choice, buy the version that doesn't list phosphates. (Though that doesn't guarantee you aren't getting some.)

3. Avoid or limit consumption of rotisserie meats, chicken or other meats with added solutions. If you must eat them, keep them as occasional indulgences.

4. Don't eat meat from fast food restaurants. (There are plenty of other reasons to avoid them, a main one being the presence of MSG and hidden forms of MSG which increase hunger and promote fat gain.)

5. Buy your poultry from health food markets that do not add enhancing solutions.  Don't assume their products don't contain phosphates. Ask to speak to the manager and ask if their meats have been treated with solutions of any type. Many foods containing phosphates are marketed with labels calling them, "All Natural."

6. Eat only unprocessed cheeses--cheddar rather than American cheese, for example.

7. Read the labels on all cold cuts and bacon you buy.  Don't buy the ones with phosphates--though unfortunately, you can't be entirely sure that omission from the label means omission from the food.

It is likely that as more of the health-conscious baby boom generation develops kidney disease as they age, more public attention will be focused on this problem and pressure will be brought on food companies and supermarkets to either omit phosphates from their foods or label the phosphate content in meaningful ways. I sure hope so.