By Tilman Nathaniel, Founder of Superfood Box
Where the Lectin Avoidance Diet Came From
The Lectin Avoidance Diet, popularized by Dr Steven Gundry, claims you should avoid all fruits and vegetables in the nightshade family and avoid legumes. First off, avoiding fruits and vegetables?! You don't hear that very often in realm of healthy eating. He claims tomatoes, potatoes, eggplants and goji berries are highly inflammatory. In the second sentence of his recent book, The Plant Paradox: The Hidden Dangers in "Healthy" Foods That Cause Disease and Weight Gain, he proclaims "After all, I'm a heart surgeon."
One reason I was skeptical is that Gundry sells his own supplements. I did a quick keyword search through Google Books to see if his book mentioned his most popular Vital Reds supplement, but there was no results. This supplement is a 4oz superfruit blend that sells for the low price of $69.95. It also seems a bit off that this supplement has 2827 customer reviews, while many of his other products have none.
Tomatoes - Anti-Inflammatory
I started with a simple search on Google Scholar: tomatoes and inflammation. In the second result I found this study:
A human study was carried out to investigate whether tomato juice, rich in natural lycopene and fortified with vitamin C, is able to reduce several biomarkers of oxidative stress and inflammation and whether the effect can be attributed to lycopene, vitamin C or any other micronutrient.
The results stated:
Drinking two glasses of tomato juice (500 ml) daily for 2 weeks reduced the inflammation marker CRP.
And they concluded:
A synergic effect between vitamin C, lycopene and other tomato micronutrients seems likely to be responsible for the beneficial effects of tomato juice on oxidative stress and inflammation.
Moving down the list of results on Google Scholar, I noticed an intriguing title: Tomatoes, Tomato-Based Products, Lycopene, and Cancer: Review of the Epidemiologic Literature. And we're off to a good start here:
Among 72 studies identified, 57 reported inverse associations between tomato intake or blood lycopene level and the risk of cancer at a defined anatomic site; 35 of these inverse associations were statistically significant. No study indicated that higher tomato consumption or blood lycopene level statistically significantly increased the risk of cancer at any of the investigated sites.
Again, they point out the lycopene content in tomatoes:
The unique biochemical properties of lycopene may render it able to protect cellular components against specific types of damage from highly reactive oxygen species. The source of the reactive compounds differs by tissue type and includes smoking, sunlight, chronic inflammation, and normal metabolic processes ( 110 - 112 ).
Next, a third study clearly indicating the anti-inflammatory properties of tomatoes, and I'm still on the first page of my Google Scholar search: Tomato juice consumption reduces systemic inflammation in overweight and obese females.
The conclusion is very clear:
Tomato juice reduces inflammation in overweight and obese females. Thus, increasing tomato intake may provide a useful approach for reducing the risk of inflammatory diseases such as CVD and diabetes, which are associated with obesity.
Potatoes - Mixed Inflammatory Reponses
Potatoes were bit of a mixed bag. Regular potatoes seem to have more evidence in favor of causing inflammation. However, purple potatoes were clearly anti-inflammatory.
My first result was an animal study which concluded:
Our results demonstrate that consumption of potato skins containing glycoalkaloids can significantly aggravate intestinal inflammation in predisposed individuals.
Next, I skimmed over a study on pigmented potatoes: Pigmented Potato Consumption Alters Oxidative Stress and Inflammatory Damage in Men. Their study showed that:
Pigmented potato consumption reduced inflammation and DNA damage in healthy adult males.
This study was "Supported by the Washington State Potato Commission and the US Potato Board" so I took it with a grain of salt.
Another study titled Potatoes and Health, a collaboration by researchers from McGill University and University of Maine, explains how potatoes have both anti-inflammatory and inflammatory effects:
However, the authors seems to lean towards an anti-inflammatory view in the summary:
There is some evidence that potato protein, resistant starches, and phosphorylated starches also contribute cholesterol-lowering properties. Phytochemicals, especially antioxidants, were implicated in reducing inflammation, a risk for cancer, cardiovascular disease, and diabetes.
Let's look at one more on the common potato for good measure. The role of potatoes and potato components in cardiometabolic health: A review
Potatoes and potato components have been shown to have favorable impacts on several measures of cardiometabolic health in animals and humans, including lowering blood pressure, improving lipid profiles, and decreasing markers of inflammation.
Now, let's consider another type of potatoes. Although, these are not a part of the nightshade family, encouraging people to avoid potatoes will naturally result in the avoidance of all types of potatoes. Numerous animal studies on Sweet Potatoes point to anti-inflammatory effects, but I didn't see any human studies coming up. Also, a number of them were discussing the anti-inflammatory effects of the plant's leaves. One really interesting study presented by Chinese researchers determined that Purple Sweet Potatoes had an anthocyanin pigment that demonstrated a " neuroprotective effect on the aging mouse brain."
PSPC (Purple Sweet Potato Color) consequently improved the spontaneous behavior and cognitive performance and enhanced the capacity of the brain inherent antioxidant or anti-inflammation. These findings about the pharmacological efficacy of PSPC would contribute to brain aging research or aging-related diseases research.
Eggplant - Anti-Inflammatory
Antioxidant and hepatoprotective activities of five eggplant varieties, a study out of Ubon Ratchathani University in Thailand, breaks down how the phenolic and flavonoid content extracted from 5 types of eggplants effected human liver cells:
The antioxidant activities of the eggplant were correlated with the total amounts of phenolic and flavonoid (r = 0.5310-0.7961). Significant correlation was found between hepatoprotective activities and total phenolic/flavonoid content (r = 0.6371-0.8842) and antioxidant activities (r = 0.5846-0.9588), indicating the contribution of the phenolic antioxidant present in eggplant to its hepatoprotective effect on t-BuOOH-induced toxicity.
This might sound a bit complex or scientific, but let me know break it down for you. Hepato simply means relating to the liver. Antioxidants are molecules which prevent cell damage caused by free radicals being released during oxidation, a process that can set off a chain reaction leading to cancer. And t-BuOOH was the substance used in the study to cause inflammation.
A study out of Iran looked at eggplant peels, recommending eggplant extract as an anticancer nutrient.
The results indicated that the toxic effect of eggplant extract was more on the cancer cells compared to the normal cells and it is notable that, the death rate of the cancer cells in three concentrations showed a significant difference compared to the normal cells. From the results of this study, it is recommended that further investigations be conducted on eggplant extract as an anticancer nutrient.
However, if you really want to cash in on your BCAAs, check out spirulina, which is listed as the best source of BCAAs by far in the vegetables category.
I was curious how goji did with a few other amino acids I’ve been reading about lately- namely tryptophan, proline and glutamic acid. They didn’t list any tryptophan but goji was also the highest source of proline and glutamic acid out of any other fruits! Proline supplements are claimed to give many people a sense of relief and happiness. Glutamic acid has been called the “brain fuel” amino acid. It detoxes the brain and helps to produce GABA, a calming neurotransmitter, in the brain.
Finding raw goji berries is difficult due to their seasonality and how quickly they go bad if not frozen or dried.
The three peppers evaluated in this study are good sources of carotenoids. The carotenoid extract obtained from guajillo peppers exhibited high antioxidant activity, safe margin of toxicity, and significant analgesic and anti-inflammatory benefits.
Still not convinced? Listen to this podcast:
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