Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
After a cancer diagnosis, the focus is understandably on monitoring the spread and resurgence of the cancer, but patients often also want to know what additional steps they themselves can take to support their body’s fight. Previously, I addressed what to eat after a cancer diagnosis. What about eating nothing at all? Fasting is purported to “ameliorate” cancers, but to support such claims, they cite studies like this on castrated mice. That’s because there are no human studies of efficacy, though there are a few case reports. For example: “Water-only fasting and an exclusively plant foods diet in the management of stage IIIa, low grade follicular lymphoma.”
Traditional chemotherapy has been the mainstay of treatment for follicular lymphoma. But in the majority of patients, the cancer surges back within a few years, and the chemo is associated with immediate and enduring toxicities, including secondary malignancies, meaning new cancers caused by the chemo drugs themselves. This raises the question of whether chemotherapy should be abandoned for the disease.
So anyway, a 42-year-old woman presented to her primary care provider with a palpable mass in her groin and was immediately sent for a CT scan. Surgical biopsy confirmed the diagnosis of a low-grade follicular lymphoma. They then found involvement in the lymph nodes in her armpit, which would make it stage 3, meaning spread throughout her body. Because it didn’t appear to be aggressive, she was just advised to follow up every three months to monitor its spread. But she didn’t want to just sit around; so, she contacted the TrueNorth Health Center in California to explore medically supervised, water-only fasting.
She had never smoked tobacco, but she had consumed the Standard American Diet; so, they started her on a whole food plant-based diet free of added salt, oil, and sugar. Then, she did 21 days on water only, before transitioning back to a diet of minimally processed plant foods, including fresh, raw fruits and vegetables, steamed and baked vegetables, whole grains and legumes, and about an ounce a day of nuts and seeds. Okay, so what happened?
On physical exam, her cancerous lymph nodes seemed to be shrinking, and indeed, on CT scan, her enlarged nodes shrunk up to 90 percent and no longer seemed to be active. Before and after.
What could it have been? She did lose weight, about 20 pounds, but follicular lymphoma does not appear to be associated with obesity, nor does BMI appear to affect clinical outcomes. It’s possible the plant-based diet alone helped. Follicular lymphoma is the second most common type of non-Hodgkin lymphoma, which itself is the most common type of blood cancer in adults. Higher intakes of dietary fiber, whole grains, and several fruits and vegetables are reported to reduce the risk of non-Hodgkin lymphoma, whereas animal-derived proteins and fat in meat and dairy may increase it.
A dietary pattern high in meats, fats, and sweets was associated with three times the risk of follicular lymphoma, and in another study, just the fat and meat was associated with up to a fivefold higher risk. But why? The thought that foods of animal origin may increase the risk of blood cancers originated from the frequent finding of an increased incidence among people who are occupationally exposed to animals and meats, like livestock and poultry farmers, butchers, and slaughterhouse workers. It must be acknowledged that animal foods are a potential source of infection by cancer-causing viruses. But it may just be the animal protein.
Excessive consumption of animal protein may encourage malignant changes through chronic persistent stimulation. The thought is that the continuous exposure to these foreign proteins may act as like a chronic irritant. The animal protein theory is bolstered by the fact that straight protein—casein milk protein—increases the number of lymphomas in rats. But that doesn’t mean the same applies to people.
Maybe it’s the hormones and antibiotics contained in meat or just the saturated fat, which may both impair the immune system and promote chronic inflammation, which may play a role in lymphoma. Now, it appears to just be animal fat consumption; so, maybe it’s just something building up in the animal fat?
There may be a link between exposure to industrial pollutants and non-Hodgkin lymphoma, and food—especially meat, milk, and fish—is the immediate source of almost all dioxins and PCBs in the general population. Dioxin-like pollutants build up in animal fat, which can then be passed along to consumers. Vegetarians may only be exposed to about 2 percent of the dioxin dose compared to the general population.
The highest single levels in the U.S. have been found in chicken, but thankfully the contamination levels are declining in all meats across the board. Furthermore, consumers may further reduce exposures to dioxin-like compounds by trimming fat before and after cooking and by thoroughly draining fat from cooked meat.
What about buying organic meat? The title kind of gives it away. When it comes to carcinogenic contaminants, the differences between organically and conventionally produced meats were surprisingly minimal, exceeding the maximum limits regardless of what kind of meat we buy. Strikingly, not only does the consumption of organically-produced meat not diminish this carcinogenic risk, but for some meat, it appeared even worse.
What can decrease your exposure to fat-soluble pesticides is fiber. And then, our good gut flora can turn fiber into butyrate, which is absorbed back into our body from the colon, and acts as a tumor suppressor––demonstrated in more than a hundred published studies, including protecting against lymphoma. It also has potent anti-inflammatory effects. That may help explain why fruit and vegetable consumption has not only been associated with decreased risk of developing lymphoma, but also been linked to improved survival. Maybe it’s all the antioxidants in plant foods, which appear protective when it comes to follicular lymphoma––but not necessarily when in supplement form. Vitamin C intake from foods, for example, may be protective, but not from supplements.
So, maybe the reason the risk of lymphomas and cancers of the bone marrow tissues are significantly lower in vegetarians and vegans is not just because of what they’re avoiding, but all the goodies they’re getting more of. The phytochemicals and antioxidants in fruits and vegetables may inhibit tumor progression via a variety of mechanisms beyond just the potential adverse effects of meat. So, given the link between fruit and vegetable intake and lymphoma survival, maybe a lymphoma diagnosis can be an important “teachable” moment to improve diet in patients. That certainly seemed to be the case here. At her six- and nine-month follow-ups, she reported strict compliance with her whole food plant-based diet, and her lymph nodes remained unpalpable. Okay, but this was published in 2015. How’s she doing now? We’ll find out next.
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