MGUS causes no symptoms. You won’t even know you have it unless your doctor finds it incidentally during routine blood work. The chance of MGUS progressing into myeloma is about 1 percent per year, which means many MGUS-stricken people may die of other causes before they develop myeloma.29 However, since multiple myeloma is basically a death sentence, scientists have been desperate to find ways to stop MGUS in its tracks.
Given the safety and efficacy of the turmeric spice component curcumin against other types of cancer cells, researchers from the University of Texas collected multiple myeloma cells and put them in a petri dish. Without any intervention, the cancer cells quadrupled within a few days—that’s how fast this cancer can grow. But when a little curcumin was added to the broth they were bathing in, the myeloma cells’ growth was either stunted or stopped altogether.30
As we’ve discovered, stopping cancer in a laboratory is one thing. What about in people? In 2009, a pilot study found that half (five out of ten) of the subjects with MGUS who had particularly high abnormal antibody levels responded positively to curcumin supplements. None (zero out of nine) of those given a placebo experienced a similar drop in antibody levels.31 Buoyed by this success, scientists conducted a randomized, double-blind, placebo-controlled trial and achieved similarly encouraging results in both patients with MGUS and those with “smoldering” multiple myeloma, an early stage of the disease.32 This result suggests that a simple spice found in the supermarket might have the ability to slow or stop this horrific cancer in a certain percentage of patients, though we won’t know more until longer studies are performed to see if these hopeful changes in blood-work biomarkers translate into changes in actual patient outcomes. In the meantime, it couldn’t hurt to spice up your diet.
Are Animal Viruses Involved in Human Blood Cancers?
The reason people eating plant-based diets appear to have much lower rates of blood cancers33 may be due to the foods they’re choosing to eat and/or choosing to avoid. To tease out the role different animal products might play in the myriad blood cancers, we would need to conduct a very large study. Enter the aptly named EPIC study, the European Prospective Investigation into Cancer and Nutrition, which did just that. As we saw in chapter 4, researchers recruited more than four hundred thousand men and women across ten countries and followed them for about nine years. If you recall, regular chicken consumption was associated with an increased risk for pancreatic cancer. Similar findings were found for blood cancers. Of all the animal products studied (including unusual categories, such as offal, or entrails and organs), poultry tended to be associated with the greatest increased risk of non-Hodgkin’s lymphoma, all grades of follicular lymphoma, and B-cell lymphomas, such as B-cell chronic lymphatic leukemia (including small lymphocytic leukemia and prolymphocytic lymphocytic leukemia).34 The EPIC study found that risk increased between 56 percent and 280 percent for every 50 grams of poultry consumed daily. For comparison, a cooked, boneless chicken breast may weigh as much as 384 grams.35
Why is there so much lymphoma and leukemia risk associated with eating such relatively small amounts of poultry? The researchers suggested this result could be a fluke, or it could be due to the drugs, such as antibiotics, that are often fed to chickens and turkeys to promote their growth. Or it might be the dioxins found in some poultry meat, which have been linked to lymphoma.36 But dairy can also contain dioxins, and milk consumption was not linked to NHL. The researchers surmised it may be the cancer-causing viruses in poultry, given that lower risk of NHL has been associated with eating meat cooked well done instead of rare (thereby inactivating any viruses).37 This suggestion is consistent with the results of the NIH-AARP study (see here), which found an association between eating just-done chicken and one type of lymphoma and lower risk of another blood cancer tied to greater exposure to the cooked meat carcinogen MeIQx.38
How could less cancer be linked to more carcinogen exposure? MeIQx is one of the heterocyclic amines created by cooking meat at high temperatures, such as baking, grilling, and frying.39 If, in the case of blood cancers, one cause is a poultry virus, then the more the meat was cooked, the more likely it is that the virus was destroyed. Cancer-causing poultry viruses—including the avian herpesvirus that causes Marek’s disease, several retroviruses like reticuloendotheliosis virus, the avian leukosis virus found in chickens, and the lymphoproliferative disease virus found in turkeys—may explain the higher rates of blood cancers among farmers,40 slaughterhouse workers,41 and butchers.42 Viruses can cause cancer by directly inserting a cancer-causing gene into a host’s DNA.43
Animal viruses can infect people who prepare meat with unpleasant skin diseases, such as contagious pustular dermatitis.44 There’s even a well-defined medical condition commonly known as “butchers’ warts” that affects the hands of those who handle fresh meat, including poultry and fish.45 Even the wives of butchers appear to be at higher risk for cervical cancer, a cancer definitively associated with wart-virus exposure.46
Workers in poultry slaughterhouses have been found to have higher rates of cancers of the mouth, nasal cavities, throat, oesophagus, rectum, liver, and blood. On a public health level, the concern here is that the cancer-causing viruses present in poultry and poultry products may then be transmitted to those in the general population who handle or eat inadequately cooked chicken.47 These results were replicated recently in the largest such investigation to date, studying more than twenty thousand workers in poultry slaughtering and processing plants. They confirmed the findings of three other studies to date: Workers in these facilities do have increased risk of dying from certain cancers, including cancers of the blood.48
Researchers are finally starting to connect the dots. The high levels of antibodies to avian leukosis/sarcoma viruses49 and to reticuloendotheliosis viruses50 recently found in poultry workers provide evidence of human exposure to these cancer-causing poultry viruses. Even line workers who simply cut up the finished product and weren’t ever exposed to live birds had elevated levels of antibodies in their blood.51 Beyond just occupational safety, the potential threat to the public, the researchers concluded, “is not trivial.”52
Elevated blood cancer rates can even be traced back to the farm. An analysis of more than one hundred thousand death certificates found that those who grew up on a farm raising animals appeared significantly more likely to develop a blood cancer later in life, whereas growing up on a farm growing only crops was not. Worst was growing up on a poultry farm, which was associated with nearly three times the odds of developing blood cancer.53
Exposure to cattle and pigs has also been associated with non-Hodgkin’s lymphoma.54 A 2003 study by University of California researchers revealed that nearly three-quarters of human subjects tested positive for exposure to the bovine leukemia virus, likely through the consumption of meat and dairy products.55 Approximately 85 percent of U.S. dairy herds have tested positive for the virus (and 100 percent on industrial-scale operations).56
However, just because people are exposed to a virus that causes cancer in cows does not mean that humans themselves can become actively infected with it. In 2014, researchers supported in part by the U.S. Army Breast Cancer Research Program published a remarkable report in a journal of the Centers for Disease Control and Prevention. They reported that the bovine leukemia virus DNA was found to be incorporated into normal and cancerous human breast tissue, effectively proving that people can also become infected with this cancer-causing animal virus.57 To date, however, the role poultry and other farm animal viruses play in the development of human cancers remains unknown.
What about the feline leukemia virus? Thankfully, pet companionship is associated with lower rates of lymphoma, which is a personal relief given how many animals I’ve shared my life with. And the longer people have had cats or dogs in their lives, the lower their risk. In one study, the lowest risk of lymphoma was found in people who had had pets for twenty years or longer. The researchers suspect the reason is connected to the fact that h
aving pets may have beneficial effects on the immune system.58
A pair of Harvard University studies suggested that diet fizzy-drink consumption may increase the risk of non-Hodgkin’s lymphoma and multiple myeloma,59 but this association was only seen among men and was not confirmed in two other large studies on aspartame-sweetened fizzy drinks.60,61 Eliminating fizzy drinks can’t hurt, though, in addition to making the dietary changes outlined above.
Plant-based diets are associated with nearly half the risk of blood cancers, protection likely to derive both from the avoidance of foods tied to liquid tumors, such as poultry, as well as the additional consumption of fruits and vegetables. Greens may be particularly useful for non-Hodgkin’s lymphoma and turmeric for multiple myeloma. The role tumor-promoting farm animal viruses play in human cancers is not known, but this should be a research priority given the potential extent of public exposure.
CHAPTER 10
How Not to Die from Kidney Disease
Letters and e-mails from patients never fail to inspire me. One note that came to mind as I was writing this chapter was from Dan, a retired NFL player. I first met him when he was forty-two. Even at that relatively young age, the former professional athlete was already taking three separate blood pressure medications. Still, his blood pressure was elevated. He was a little overweight, maybe by twenty-five pounds. He and his significant other waited around after one of my talks to see me.
Dan’s physician had just told him that his kidneys were starting to show signs of damage due to his blood pressure. The first thing I asked was if he was taking his medication as prescribed, since many people skip their blood pressure medications because of their unpleasant side effects. Yes, he assured me, he was. He showed me a checklist he carried around to keep track of his medication. He asked me what supplements he could add to the list to help his kidneys.
I told him that no matter what he might have seen on the Internet, there’s no such magic pill, but if he filled up his plate with lots of whole, healthy foods each day, the damage might be stopped or even reversed. Well, Dan took this advice to heart (and to kidney!), and he allowed me to share his e-mail:
Well, I went home that night and we cleaned house. Got rid of everything that didn’t grow out of the ground, everything processed. And guess what, over the next year, I lost my beer belly and the high blood pressure. Life is so much better without those medications—they made me feel so tired all the time. And my kidney function is back to normal. It makes me mad that no one told me this sooner and that I had to feel so bad before I felt better.
It’s easy to take your kidneys for granted, but they work around the clock, like a high-tech, nonstop water filter for your blood. They process up to 150 liters of blood every twenty-four hours just to make the 1–2 liters of urine you pee out each day.
If your kidneys do not function properly, metabolic waste products can accumulate in the blood and eventually lead to such symptoms as weakness, shortness of breath, confusion, and abnormal heart rhythms. Most people with deteriorating kidney function, however, don’t experience any symptoms at all. If your kidneys fail completely, you will either need a new one (i.e., need a kidney transplant) or have to go on dialysis, a process by which a machine artificially filters the blood. But kidney donors are in short supply, and the average life expectancy of a person on dialysis is less than three years.1 It’s better to keep your kidneys healthy in the first place.
Although your kidneys can fail suddenly in response to certain toxins, infections, or urinary blockage, most kidney disease is characterized by a gradual loss of function over time. A national survey found that only 41 percent of Americans tested had normal kidney function, a drop from 52 percent about a decade earlier.2 Approximately one in three Americans over the age of sixty-four may suffer from chronic kidney disease (CKD),3 though three-quarters of the millions affected may not even know they have it.4 More than half of American adults currently aged thirty to sixty-four are expected to develop chronic kidney disease during their lifetimes.5
Why, then, aren’t millions of people on dialysis? Because kidney malfunction can be so damaging to the rest of the body that most people don’t live long enough to reach that stage. In a study in which more than a thousand Americans over age sixty-four with CKD were followed for a decade, only one in twenty developed end-stage kidney failure. Most of the others had already died, with cardiovascular disease killing more than all other causes combined.6 That’s because our kidneys are so critical to proper heart function that patients under age forty-five with kidney failure can be a hundred times more likely to die of heart disease than those with working kidneys.7
The good news? The diets that are healthiest for our hearts—those centered around unprocessed plant foods—may be the best way to prevent and treat kidney disease as well.
Damaging Your Kidneys with Diet
Kidneys are highly vascular organs, meaning they’re packed with blood vessels, which is why they look so red. We’ve already seen that the standard American diet can be toxic to blood vessels in the heart and the brain—so what might it be doing to the kidneys?
Putting that question to the test, researchers at Harvard University followed thousands of healthy women, their diets, and their kidney function for more than a decade8 to look for the presence of protein in the women’s urine. Healthy kidneys work hard to retain protein and other vital nutrients, preferably filtering toxic or useless wastes out of the bloodstream via our urine. If the kidneys are leaking protein into urine, it’s a sign that they may be starting to fail.
The researchers found three specific dietary components associated with this sign of declining kidney function: animal protein, animal fat, and cholesterol. Each of these is found in only one place: animal products. The researchers found no association between kidney function decline and the intake of protein or fat from plant sources.9
One hundred and fifty years ago, Rudolf Virchow, the father of modern pathology, first described fatty degeneration of the kidney.10 This concept of lipid nephrotoxicity, or the idea that fat and cholesterol in the bloodstream could be toxic to the kidneys, has since been formalized,11 based in part on studies that found plugs of fat clogging up the works in autopsied kidneys.12
The link between cholesterol and kidney disease has gained such momentum in the medical community that cholesterol-lowering statin drugs have been recommended to slow its progression.13 But wouldn’t it be better (not to mention safer and cheaper) to treat the underlying cause of the disease by eating healthier?
Which Type of Protein Is Better for Our Kidneys?
In the two decades between 1990 and 2010, the leading causes of death and disability remained relatively constant. As noted in chapter 1, heart disease is still the leading cause of loss of health and life. Some diseases, such as HIV/AIDS, have slid down the list, but among the diseases whose incidence has increased the most over the past generation is chronic kidney disease. The number of deaths has doubled.14
This has been blamed on our “meat-sweet” diet.15 Excess table sugar and high-fructose corn syrup consumption is associated with increased blood pressure and uric acid levels, both of which can damage the kidney. The saturated fat, trans fat, and cholesterol found in animal products and junk food are also associated with impaired kidney function, and meat protein increases the acid load to the kidneys, boosting ammonia production and potentially damaging our sensitive kidney cells.16 This is why a restriction of protein intake is often recommended to chronic kidney disease patients to help prevent further functional decline.17
But all protein isn’t created equal. It’s important to understand that not all protein has the same effect on your kidneys.
High animal protein intake can have a profound influence on normal human kidney function by inducing a state called hyperfiltration, a dramatic increase in the workload of the kidney. Hyperfiltration isn’t harmful if it occurs only occasionally. We all have built-in reserve kidney function—so much so that people can liv
e with only one kidney. The human body is thought to have evolved the capacity to handle intermittent large doses of protein from our remote hunting and scavenging days. But now many of us are ingesting large doses of animal protein day after day, forcing our kidneys to call on their reserves continuously. Over time, this unrelenting stress may explain why kidney function tends to decline as people age, predisposing even otherwise healthy people to progressive deterioration of kidney function.18
The reason those who eat a plant-based diet appear to have better kidney function was originally thought to be due to their lower overall protein intake.19 However, we now know that it’s more likely due to the fact that the kidneys appear to handle plant protein very differently from animal protein.20
Within hours of consuming meat, your kidneys rev up into hyperfiltration mode. This is true of a variety of animal proteins—beef, chicken, and fish appear to have similar effects.21 But an equivalent amount of plant protein causes virtually no noticeable stress on the kidneys.22 Eat some tuna, and within three hours, your kidney filtration rate can shoot up 36 percent. But eating the same amount of protein in the form of tofu doesn’t appear to place any additional strain on the kidneys.23
Could substituting plant protein for animal protein help slow the deterioration of kidney function? Yes, half a dozen clinical trials have shown that plant protein replacement can reduce hyperfiltration and/or protein leakage,24,25,26,27,28,29 but all these studies were short term, lasting fewer than eight weeks. It wasn’t until 2014 that a six-month, double-blind, randomized, placebo-controlled clinical trial was performed examining how the kidneys process soya protein versus dairy protein. Consistent with the other studies, plant protein was found to help preserve function in ailing kidneys.30
Why does animal protein cause the overload reaction while plant protein doesn’t? Because of the inflammation animal products can cause. Researchers discovered that after giving study subjects a powerful anti-inflammatory drug along with animal protein, the hyperfiltration response and protein spillage disappeared.31
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