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Broccoli Boosts Liver Detox Enzymes

Researchers just found out that the boost in detoxifying enzymes triggered by cruciferous vegetable consumption may last for weeks!

Last spring in my post The Best Detox I described this amazing phenomenon in which a phytonutrient produced by broccoli can enhance the function of our so-called phase II enzyme system that aids in the excretion of foreign molecules. For example if you feed people broccoli and Brussels sprouts, they clear caffeine quicker as you can see in my 3-min video Prolonged Liver Function Enhancement From Broccoli. This means that if you eat a lot of these healthy vegetables you’d actually have to drink more coffee to get the same buzz because your liver is so revved up.

What about the carcinogens that I wrote about in my last three posts, Estrogens in Cooked Meat, Avoiding Cooked Meat Carcinogens, and Foods That May Block Cancer Formation? In the studies on Long Island, women that established increased breast cancer risk in those eating grilled meats found that the risk appeared greatest in women with the low fruit and vegetable consumption. Maybe having a side of broccoli can help your body deal with the carcinogen load? Researchers decided to put it to the test.

In my video Prolonged Liver Function Enhancement video I detail a study in which subjects were fed cooked meat meals with and without broccoli and Brussels sprouts. In the video you can see how dramatically the levels of these carcinogenic compounds circulating in their bodies drops. Now this wasn’t a surprise; that’s what cruciferous vegetables do—boost our liver’s ability to clear chemicals from our body. What blew the researchers away was the fact that when the veggies were taken away liver function remained enhanced–even two weeks later.

So there appears to be a prolonged beneficial effect of cruciferous vegetable consumption. You can eat broccoli days or even weeks before the big barbeque and still retain some protection. Of course if you grill veggie burgers instead it would be a non-issue. Since heterocyclic amines are byproducts of muscle tissue reacting to high heat, you can even deep-fry plant foods and still none of these carcinogens are formed.

For more on broccoli’s superpowers see my video Sometimes the Enzyme Myth Is True. You can overdo it, but apparently only at extremely high doses (see Liver Toxicity Due to Broccoli Juice, Overdosing on Greens, and How Much Broccoli Is Too Much?).

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

9 responses to “Broccoli Boosts Liver Detox Enzymes

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  1. But what about the polyunsaturated fats in veggie burgers? Would that be a problem if you fried or barbecued them?

    1. Why are you using that product if it has such additives?
      And “fried them”? Since when is a refined oil healthy cold or heated?

      Yes, any of the refined fats are a problem!

      Leave them out by using either a better product, or making bean burgers or mushroom burgers sans the additional refined fats and additives.

  2. Before I was diagnosed with stage 3 breast cancer I was on something called DIM for a while which said it detoxed and enhanced the elimination of estrogen. I didn’t take much as I was scared. In hindsight if I had eaten my brassica family raw I wouldn’t be diagnosed. The supplement is made from one of the metabolites of broccoli. Luckily for a year before diagnosis I was on natural progesterone. I am five years out natirally and call myself furious curious cancer survivor on google.

  3. Does it make a difference if the broccoli is cooked or eaten raw? Also, do you get the same effect by including broccoli in a blended concoction?

    1. Hopefully this will help…

      “Nitrate and nitrite levels in fresh and frozen broccoli. Effect of freezing and cooking;

      J.C. Huarte-Mendicoa,I. Astiasarán, J. Bello

      Departamentode Bromatología, Toxicología y Tecnología de Alimentos, Facultad de Farmacia, Universidad de Navarra, Irunlarrea, s/n, 31008, Pamplona, Spain”


      Nitrite and nitrate levels in broccolis coming from different cultures from the south of Navarra (Spain) were analyzed. Fresh products had only traces of nitrites and low levels of nitrates (48–97 ppm KNO3). Industrial freezing gave rise to an increase in the nitrate levels (127–232 ppm KNO3), probably as a consequence of high levels in the processing water. Cooking decreased nitrate levels (between 22 and 79%), there being no differences in the levels of reduction between fresh and frozen vegetables. Nitrite levels were scarcely affected either by freezing or by cooking.”

      And since the levels of nitrites/nitrates are so low, the value in chewing this particular veggie in order to ‘prime the proton pump’ facilitating nitric oxide production is minimal, it would seem that raw is best (especially broccoli sprouts – see the video Brocoli Sprouts here at , but if cooking will increase one’s eating, steam it and minimize vitamin loss.

  4. I particularly appreciate your information on ‘the dangers of a vegan diet’ such as “overdosing on greens”. I am interested in fertilisers such as may be used on herbs for example. Can they be over-fertilised, as sometimes, even at farmers markets, they can look too green and have too strong a flavour. Perhaps they are erroniously grown out of season?

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