Organic versus Conventional: Which has More Nutrients?

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Are organic foods safer and healthier than conventional alternatives? Those are two separate questions. Some consumers are interested in getting more nutrients; others are more concerned about getting fewer pesticides. Let's do nutrition first.

As seen in my video, Are Organic Foods More Nutritious?, hundreds of studies have been reviewed and researchers didn't find significant differences for most of the traditional nutrients like vitamins and minerals. They concluded that despite the widespread perception that organically produced foods are more nutritious, they didn't find robust evidence to support that perception. They did, however, find higher levels of phenolic phytonutrients in organic.

These so-called "secondary metabolites" of plants are thought to be behind many of the benefits ascribed to eating fruits and vegetables. Organic fruits and vegetables had between 19 and 69% more of a variety of these antioxidant compounds. The theory was that these phytonutrients are created by the plant for its own protection. For example, broccoli releases the bitter compounds like sulforaphane when the plant is chewed to ward off those who might eat it. Bugs take one bite and say, "Ew, this tastes like broccoli!" But pesticide-laden plants are bitten less by bugs and so may be churning out fewer of these compounds. Plants raised organically, on the other hand, are in a fight for their lives and may necessarily have to produce more protection. That was the theory anyway, but we don't have good evidence to back it up. The more likely reason has to do with the fertilizer; plants given high dose synthetic nitrogen fertilizers may divert more resources to growth rather than defense.

These antioxidants may protect the plant, but what about us? More antioxidant phytonutrients are found in organic vegetables and so yes, they displayed more antioxidant activity, but also more antimutagenic activity. Researchers exposed bacteria to a variety of mutagenic chemicals like benzopyrene, the polycyclic aromatic hydrocarbon found in barbecued meat, or IQ, the heterocyclic amine found in grilled/broiled/fried meats (as well as cigarette smoke), and there were fewer DNA mutations in the petri dishes where they added organic vegetables compared to the petri dishes where they added conventional vegetables.

Preventing DNA damage in bacteria is one thing, but what about effects on actual human cells? Organic strawberries may taste better, and have higher antioxidant activity and more phenolic phytonutrients, but what happens when you stack them up head-to-head against human cancer cells? Extracts from organically grown strawberries suppressed the growth of colon cancer cells and breast cancer cells significantly better than extracts from conventional strawberries. Now this was dripping strawberries onto cancer cells growing in a petri dish, but as I showed in Strawberries versus Esophageal Cancer, there are real life circumstances in which strawberries come into direct contact with cancerous and precancerous lesions, and so presumably organic strawberries would work even better, but they haven't yet been tested in clinical trials.

Although in vitro studies show higher antioxidant and antimutagenic activity as well as better inhibition of cancer cell proliferation, clinical studies on the impact of eating organic on human disease simply haven't been done. Based on antioxidant phytonutrient levels, organic produce may be considered 20 to 40% healthier, the equivalent of adding one or two serving's worth to a five-a-day regimen. But organic produce may be 40% more expensive, so for the same money you could just buy the extra servings worth of conventional produce. From a purely nutrients-per-dollar standpoint, it's not clear that organic foods are any better. But people often buy organic foods to avoid chemicals, not because they are more nutritious. For more on the best available science comparing the nutritional content, pesticide risk, heavy metal toxicity, and food poisoning risk of organic versus conventionally raised foods )including practical tips for making your own DIY fruit and veggie wash), see:

I imagine that the reaction to this series will be similar to that for the one I did on GMO foods, riling up critics on both sides of the debate:

More on the nutritional implications of stressed-out plants here:

Production method aside, in vitro, Which Fruit Fights Cancer Better?

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Sally Plank / Flickr. This image has been modified.

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How to Cook Broccoli

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When I used to teach medical students at Tufts, I gave a lecture about this amazing new therapeutic called "iloccor-B." I'd talk about all the new science, all the things it could do, its excellent safety profile. Just as they were all scrambling to buy stock in the company and prescribe it to all their patients, I'd do the big reveal. Apologizing for my "dyslexia," I would admit that I'd got it backwards. All this time I had been talking about broccoli.

The main active ingredient in broccoli is thought to be sulforaphane, which may protect our brains, protect our eyesight, protect our bodies against free radicals, boost our detoxification enzymes, and help prevent and treat cancer.

In my videos The Best Detox and Sometimes the Enzyme Myth is the Truth, I talked about how the formation of sulforaphane is like a chemical flare reaction, requiring the mixing of a precursor compound with an enzyme, which is destroyed by cooking. This may explain why we get dramatic suppression of cancer cell growth from raw broccoli, cauliflower and Brussels sprouts, but hardly anything from boiled, microwaved or steamed (except for microwaved broccoli, which actually retains some cancer fighting abilities). But who wants to eat raw Brussels sprouts?

There is a strategy to get the benefits of raw in cooked form. In raw broccoli, the sulforaphane precursor, called glucoraphanin, mixes with the enzyme (myrosinase) when you chew or chop it. If given enough time--such as when sitting in your upper stomach waiting to get digested--sulforaphane is born. The precursor and sulforaphane are resistant to heat and therefore cooking, but the enzyme is destroyed. No enzyme = no sulforaphane.

That's why I described the "hack and hold" technique--if we chop the broccoli, Brussels sprouts, kale, collards, or cauliflower first and then wait 40 minutes, we can cook them all we want. The sulforaphane is already made; the enzyme has already done its job, so we don't need it anymore.

When most people make broccoli soup, for example, they're doing it wrong. Most people cook the broccoli first, then blend it. We now know it should be done the exact opposite way. Blend it first, wait, and then cook it.

What if we're using frozen broccoli, though? In my video, Second Strategy to Cooking Broccoli, you can see the amount of sulforaphane in someone's body after they eat broccoli soup made from fresh broccoli versus from frozen broccoli. The difference is dramatic. Commercially produced frozen broccoli lacks the ability to form sulforaphane because vegetables are blanched (flash-cooked) before they're frozen for the very purpose of deactivating enzymes. This prolongs shelf life in the frozen foods section, but the myrosinase is dead by the time you take it out of your freezer. It doesn't matter how much you chop it, or how long you wait, no sulforaphane is going to be made. This may be why fresh kale suppresses cancer cell growth up to ten times more than frozen.

The frozen broccoli is still packed with the precursor--remember that's heat resistant--and we could get lots of sulforaphane out of the frozen broccoli by adding some outside enzyme. Where do we get myrosinase enzyme from? Researchers just buy theirs from a chemical company. But we can just walk into any grocery store.

All cruciferous vegetables have this myrosinase. Mustard greens, a cruciferous vegetable, grow out of little mustard seeds, which we can buy ground up in the spice aisle as mustard powder. If we sprinkled some mustard powder on our cooked frozen broccoli, would it start churning out sulforaphane? We didn't know...until now.

Boiling broccoli prevents the formation of any significant levels of sulforaphane due to inactivation of the enzyme. However, researchers from the University of Reading found that the addition of powdered mustard seeds to the heat processed broccoli significantly increased the formation of sulforaphane. In the video I mentioned earlier, Second Strategy to Cooking Broccoli, you can see the amount of sulforaphane in boiled broccoli versus the amount after half a teaspoon or a teaspoon of mustard powder is added. Both a half teaspoon and a full teaspoon increase sulforaphane by the same amount, suggesting that we could use even use less mustard powder for the same effect. Therefore, although domestic cooking leads to the deactivation of myrosinase and stops sulforaphane formation, the addition of powdered mustard seeds to cooked cabbage-family vegetables provides a natural source of the enzyme such that it's practically like eating them raw.

So, if we forget to chop our greens in the morning for the day, or are using frozen, we can just sprinkle some mustard powder on top at the dinner table and we're all set. Daikon radish, horseradish, or wasabi--all cruciferous vegetables packed with the enzyme--work as well. Just a quarter teaspoon of Daikon radish root for seven cups of broccoli worked--just a tiny pinch can do it. Or you can add a small amount of fresh greens to your cooked greens, because the fresh greens have myrosinase enzyme that can go to work on the cooked greens.

I love kitchen chemistry--it totally revolutionized my daily greens prep. One of the first things I used to do in the morning is chop my greens for the day, so when lunch and supper rolls around they'd be good to go. But now with the mustard powder plan, I don't have to pre-chop.

This helps explain the results I presented in Raw Broccoli and Bladder Cancer Survival.

OK, but what's so great about this sulforaphane stuff? For a taste, see:

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Jessica Spengler / Flickr

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How Do Broccoli Supplements Compare to Sprouts?

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Your parents would have been smart to tell you to to "eat your broccoli." But what about broccoli sprouts? Or broccoli supplements?

There have been a number of randomized, double-blind, placebo-controlled clinical trials on the use of broccoli sprouts as a complementary treatment in diabetes to reduce oxidative stress, inflammation, and insulin resistance and fasting blood sugars.

In my video, Biggest Nutrition Bang for Your Buck, I describe how to grow our own sprouts simply and quickly in five days. New science suggests, though, that it's even simpler and quicker than I described. If we look at other sprouts, their antioxidant phytonutrients appear to peak around sprouting day five (up to 10-fold higher than day two), but the sulforaphane content in broccoli sprouts appears to peak at around 48 hours, so 2-day-old sprouts may be even better (See Sulforaphane: From Broccoli to Breast).

What if we don't enjoy eating broccoli or broccoli sprouts but still want the benefits of the broccoli phytonutrients? Do the broccoli supplements on the market work? One group of researchers tested BroccoMax, which boasts a half pound of broccoli's worth in every capsule. Researchers compared six capsules a day to a cup of broccoli sprouts. In the video, Broccoli: Sprouts vs. Supplements, you can see the spike in broccoli phytonutrients in the bloodstream of those eating sprouts. The cup of broccoli sprouts dramatically outperforms the six capsules at a small fraction of the cost. The researchers conclude that the bioavailability of broccoli phytonutrients is dramatically lower when subjects consume broccoli supplements compared to the whole food.

What's so great about broccoli sprouts? See: The Best Detox and Sulfurophane: From Broccoli to Breast.

They can be overdone, though. See: How Much Broccoli is Too Much?

More on cruciferous and cancer here:

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: whologwhy / Flickr

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