Welcome to the Nutrition Facts podcast. I’m your host Dr. Michael Greger. I am thrilled that you have decided to join me today. Because the more I learn about latest nutrition research – the more convinced I am that this information can make a real difference in all of our lives. And I like nothing better – than sharing it with you.
There is no cure for psoriasis yet – but there are different schools of thought on treatment. In our first story, Aloe gel is put to the test head-to-head versus steroids.
Psoriasis is a chronic, inflammatory skin disease that affects about one in 40 people, making it “one of the most frequent chronic skin diseases worldwide.” There’s lots of drugs for it, some of which cost more than $100,000 a year to get a response. There are cheaper drugs like cyclosporine, but it carries the “long-term risk of kidney damage, hypertension, and malignancies.” The drug can cause cancer; kidney toxicity in “more than 50% of the patients” treated long-term; and, in terms of risk of malignancies, up to 42 times the rate of cancer. And, it doesn’t even work that well, keeping the disease at bay in a little more than half of patients over a four-month period. There’s got to be a better way.
What about plants? “Topical botanical agents for the treatment of psoriasis.” Well, aloe vera gel is said to possess “anti-inflammatory, anti-itching, and wound-healing properties.” Yeah, but as I described before, when it was put to the test for wound healing, it actually made things worse. “The exploitation of aloe preparations has been accompanied too often by misinformation and exaggerated claims,” but there is some “impressive” evidence. For example, to test its anti-inflammatory properties, it was tested head-to-head against steroids for mustard gas exposure.
Mustard gas is probably the most popular chemical warfare agent, starting in World War I. The last widespread military use was in the 80s during the Iraq-Iran war, with more than 100,000 exposed and many “still suffering from the long-term complications,” predominantly itching. Even decades after surviving a gas attack, 70% to 90% are still suffering.
Topical steroids are the most frequently administered medications, and they help. But long-term use “is not recommended, and is associated with” a variety of side effects. Therefore, how about safer agents, like aloe vera?
“Sixty-seven…chemical warfare-injured [vets] were randomized to apply an [aloe] vera/olive oil cream” or the steroids, and the aloe vera mixture appeared to work as well as the drug.
Okay; well then, let’s give it a try for the management of psoriasis. By the end of the month-long study, the aloe vera cream had cured 83% of the patients, compared to the placebo cure rate of less than 10%, “resulting in significant clearance of the psoriatic plaque” skin lesions.
All right, but that’s compared to an inactive placebo. How about compared to steroids? Aloe was found to be “more effective…in reducing the clinical symptoms.”
In this “double-blind, placebo-controlled study of a commercial Aloe vera gel in the treatment of slight to moderate psoriasis,” things got better in 70% of the aloe-treated sites, but 80% of the placebo-treated areas improved. The placebo beat out the aloe. “The high response rate of the placebo gel indicated a possible effect in its own right.” The placebo was just basically xanthan gum and water, and they were like, hey, instead of aloe failing, maybe xanthan gum just works, too!
All in all, the “results on the effectiveness of aloe vera for psoriasis are contradictory.” But applying it on the skin appears safe, so I figure why not give it a try.
In our next story, we learn about two ways in which salt may drive autoimmune diseases such as multiple sclerosis, psoriasis, type I diabetes, Sjögren’s syndrome, asthma, and rheumatoid arthritis.
Millions suffer from asthma attacks triggered by exercise. Within five minutes of starting exercising, people can get short of breath, start coughing and wheezing, such that lung function significantly drops. But, on a high-salt diet, the attack is even worse; whereas, on a low-salt diet, there’s hardly a significant drop in function at all.
To figure out why, researchers had them all cough up sputum from their lungs, and those on the high-salt diet ended up with triple the inflammatory cells, and up to double the concentration of inflammatory mediators. But why? What does salt intake have to do with inflammation? We didn’t know, until now.
“The ‘Western diet,’ high in saturated fat and salt, has long been postulated as one potential…cause for the increasing incidence of autoimmune diseases in developed countries…” The rapidly increasing incidence of autoimmune diseases may be due to an overactivation of immune cells, called helper 17 cells. “The development of…multiple sclerosis, psoriasis, type I diabetes,…Sjögren’s syndrome, asthma, and rheumatoid arthritis” have all been “shown to involve this Th17-driven inflammation.” And, one trigger for the activation of those Th17 cells may be elevated levels of salt in our bloodstream. “The sodium content of processed foods and ‘fast food’…can be more than 100 times higher in comparison to similar homemade meals.”
And, sodium chloride, salt, appears to drive autoimmune disease by the induction of these disease-causing Th17 cells. Turns out there’s a salt-sensing enzyme, responsible for triggering the formation of these Th17 cells.
Organ damage caused by high-salt diets may also activate another type of inflammatory immune cell. A high-salt diet can overwork the kidneys, starving them of oxygen, triggering inflammation. The more salt they gave people, the more activation of inflammatory monocyte cells, associated with “high-salt intake induced” kidney oxygen deficiency. But, this study only lasted two weeks. What about long term?
One of the difficulties in doing sodium experiments is that it’s hard to get free-living folks to maintain a specific salt intake. You can do what are called metabolic ward studies, where you essentially lock people in a hospital ward for a few days, and control their food intake. But, you can’t do that long term—unless you can lock people in a space capsule. Mars520 was a 520-day space flight simulation to see how people might do on the way to Mars and back.
What they found was that those on a “high-salt diet displayed a markedly higher number of monocytes,” which are a type of immune cell you often see increased in settings of chronic inflammation and autoimmune disorders.
This may “reveal one of the consequences of excess salt consumption in our everyday lives,” since that so-called high-salt intake may actually just be the average-salt intake. Furthermore, there was an increase in the levels of pro-inflammatory mediators, and a decrease in the level of anti-inflammatory mediators—suggesting that a high-salt diet has the “potential to bring about an]excessive immune response,” which may damage the immune balance, and result in “either difficulties in getting rid of inflammation or even an increased risk of autoimmune disease.”
What if you already have an autoimmune disease? “Sodium intake is associated with increased disease activity in multiple sclerosis.” If you follow MS patients for a few years, those eating more salt had three to four times the “exacerbation rate,” three times more likely to develop new MS lesions in their brains, and on average, had eight more brain lesions, fourteen in their brain, compared to six in the low-salt group. So, the next step is to try treating patients with salt reduction and see if they get better. But, since reducing our salt intake is a healthy thing to do anyway, I don’t see why anyone should have to wait.
In our final story, we hear about an elegant experiment in which the blood of those eating different types of spices—such as cloves, ginger, rosemary, and turmeric—is tested for anti-inflammatory capacity.
Once in a while, I come across a study that’s so juicy, I do an entire video about it. It’s like my “Which Fruit Fights Cancer Better?” video, or the “Best Cooking Method” one, or that one comparing thousands of foods. Well, this is one such study.
A group of researchers at U of F Gainesville and Penn State set up an elegant experiment. We’ve known, ounce per ounce, herbs and spices have some of the greatest antioxidant activities known—but, that’s in a test tube. Before we can ask if an herb or spice has health benefits, it’s first necessary to determine whether it’s bioavailable. This has never been done, until now.
They could have [gone] the easy route, and just measured the change in antioxidant level in one’s bloodstream before and after consumption. But, the assumption that the appearance of antioxidant activity in the blood is an indication of bioavailability has a weakness. Maybe more gets absorbed than we think, but doesn’t show up on antioxidant tests, because it gets bound to proteins or cells. So, they attempted to measure physiological changes in the blood. They were interested in “whether absorbed compounds would be able to protect [white blood cells] from an oxidative or inflammatory injury”—whether it would protect the strands of our DNA from breaking when confronted by free radicals. They also wondered if the consumption of herbs and spices “might alter…cellular inflammatory response[s] in the presence of a physiologically relevant inflammatory insult.” What does that all mean?
Well, what they did was take a bunch of people, and had each of them eat different types of spices for a week. There are so many really unique things about this study, but one was that the quantity that study subjects consumed was based on the usual levels of consumption in actual food. Like, the oregano group was given a half-teaspoon a day—the kinds of practical quantities people might actually eat once in a while. Then, at the end of the week, they drew blood from the dozen or so people they had adding black pepper to their diets that week, and compared the effects of their blood to the effects of the blood of the dozen on cayenne, or cinnamon, or cloves, or cumin. They had about ten different groups of people eating about ten different spices.
Then, they dripped their plasma (the liquid fraction of their blood) onto human white blood cells in a petri dish that had been exposed to an inflammatory insult. They wanted to pick something really inflammatory, so they chose oxidized cholesterol, which is like what you’d get in your bloodstream after eating something like fried chicken. So, they jabbed the white blood cells with oxidized cholesterol, and then measured how much TNF they produced in response.
Tumor necrosis factor is a powerful inflammatory cytokine, infamous for the role it plays in autoimmune attacks, like inflammatory bowel disease. Compared to the blood of those who ate no spices for a week, was the blood of those eating black pepper able to significantly dampen the inflammatory response? No. What about any of these other spices? Cloves, ginger, rosemary, and turmeric were able to significantly stifle the inflammatory response. And, remember, they weren’t dripping the spices themselves on these human white blood cells, but the blood of those who ate the spices. So, it represents what might happen when cells in our body are exposed to the levels of spices that circulate in our bloodstream after normal daily consumption. Not megadoses in some pill—just the amount that makes our spaghetti sauce taste good, or our pumpkin pie, or curry sauce.
There are drugs that can do the same thing. Tumor necrosis factors are such “major mediators of inflammation and inflammation-related diseases” that there are these TNF-blocking drugs on the market for the treatment of inflammatory diseases—like osteoarthritis, inflammatory bowel disease, psoriasis, ankylosing spondylitis—which rake in, collectively, more than $20 billion a year, because drug companies charge people $15,000 to $20,000 a year for the drug. At that price, the side effects better be hugs and rainbows. But, no, these drugs carry a black label warning because they can cause things like cancer and heart failure. If only there were a cheaper, safer solution.
Curcumin, the yellow pigment in turmeric, is a spice that’s a tad cheaper, and safer. But, does it work outside of a test tube? There’s evidence that it may help in all the diseases for which TNF blockers are currently being used. And so, with health care costs and safety being such major issues, this golden spice, turmeric, may help provide the solution.
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