Precision Nutrition Blog

The power of the phytochemical

by John Berardi, Ph.D.

Phytochemicals are defined as non-nutritive chemicals found in plants. However, despite their “non-nutritive” status, these powerful little molecules can impact your health in amazing and surprising ways.

And while scientists have only isolated a few of these in the laboratory, it’s estimated that there are more than a thousand phytochemicals appearing in our food supply.

Why should you care?

Well, current research indicates that many of these chemicals can impact everything from your hormonal status, to your disease risk, to the medications you take, to your ability to fight off colds and infections.

Common phytochemicals

Now, you’re probably familiar with some of these little powerhouses, including:

  • Resveratrol in grapes/grape skins
  • Isoflavones in soy
  • Lycopene in tomatoes
  • Lutein in spinach
  • Naringenin in grapefruit

Yet there are hundreds more you should be aware of – and taking advantage of in your diet.

To help get you on the right track, check out the table below.  In it, we review a host of the most studied phytochemicals and their biological effects.

Phytochemicals, foods, and effects

Class Food Source(s) Action(s)
Phytoestrogens (Isoflavones) Soy products, flaxseed, seeds and nuts, yams, alfalfa and red clover sprouts, licorice root (not candy) May block some cancers. Aid in menopausal symptoms. Help improve memory.
Phytosterols Plant oils, corn, soy, sesame, safflower, wheat, pumpking Block hormonal role in cancers. Inhibit uptake of cholesterol from the diet.
Saponins Yams, beets, beans, cabbage, nuts, soybeans May prevent cancer cells from multiplying.
Terpenes Carrots, yams, winter squash, sweet potatoes, apples, cantaloupe Antioxidants - protect DNA from free radical-induced damage.
  Tomatoes, tomato-based products Help block UVA and UVB. May help protect against cancers (prostate, etc).
  Citrus fruits (flavonoids), apples (quercetin) Promote protective enzymes in the liver. Antiseptic properties.
  Spinach, kale, beet and turnip greens, cabbage Protect eyes from macular degeneration.
  Red chili peppers Prevent carcinogens from binding to DNA.
Phenols Fennel, parsley, carrots, alfalfa, cabbage, apples Prevent blood clotting. May have anti-cancer properties.
  Citrus fruits, broccoli, cabbage, cucumbers, green peppers, tomatoes Antioxidant function. Flavonoids block membrane receptor sites for certain hormones.
  Grape seeds, apples Strong antioxidants. Fight germs and bacteria. Strengthen immune system, veins, and capillaries.
  Grapes (skins) Antioxidant and antimutagen properties. Promote detoxification. Act as carcinogen inhibitors.
  Yellow and green squash Antihepatotoxic and antitumor properties.
Sulfur compounds Onions, garlic Promote liver enzyme activity. Inhibit cholesterol synthesis. Reduce triglycerides. Lower blood pressure. Improve immune function. Fight infection, germs, and parasites.

Drugs, hormones, DNA, and more

In addition to the properties above, some of these phytochemicals are so powerful that they can influence our response to drugs.  Indeed, naringenin, in addition to serving as an antioxidant, free radical scavenger, anti-inflammatory chemical, carbohydrate metabolism promoter, and immune system modulator, also inhibits the cytochrome P450 enzyme system in the liver.

This system is responsible for first pass metabolism of numerous drugs.  Thus individuals taking statin medications for high cholesterol are instructed to avoid grapefruit because naringenin will inhibit the breakdown of statins and cause a dangerous level to accumulate in the body.  Powerful stuff!

Interestingly, phytochemicals can help the body ward off disease through various mechanisms:

Many of them function as antioxidants, helping to scavenge free radicals.  Yams (containing carotenoids) are a great example.  They can help prevent some of the oxidative damage associated with free radicals, improving cancer and heart disease prognosis.ease.

Phytochemicals may also influence hormonal function.  An example of this would be the isoflavones found in soy and the lignans found in flax.  These can mimic estrogen in the body, in many cases blocking estrogen receptor sites, diminishing estrogen’s effects on certain tissues.

Further to the hormonal function example above, there are also enzymes in the liver that can make estrogen less effective.  These enzymes can be up-regulated by indoles, a type of phytochemical found in cruciferous vegetables.

Phytochemicals such as capsaicin, which makes peppers spicy, may help protect DNA from carcinogens.

Have you ever heard that garlic is anti-bacterial?  That’s the effect of allicin, a phytochemical found in garlic. Interestingly, many other phytonutrients have anti-bacterial and anti-viral abilities. For example, anthocyanins (red, purple, and/or blue plant pigments) found in many fruits can actually prevent the adhesion of pathogens to cell walls.  Thus cranberries can help prevent urinary tract infections.

Whole food synergy

Armed with some of this great information, what’s next?  Well, if I were you, I’d focus on filling up my diet with a rich diversity of the whole foods mentioned above.

Indeed, a varied diet rich in whole foods offers the best combination of dietary micronutrients and phytochemicals. Unfortunately, in today’s nutritional world, we’re replacing many of these whole foods with  processed convenience foods.  Stuff that’s low in vitamins, minerals, and phytochemicals. Not good.

Few people realize that nutrient deficiencies unseen for hundreds of years are beginning to reappear.  And with these deficiencies come poor health, increased disease risk, obesity, and more.

Now, a lot of physiologists, docs, and nutritionists, including the experts at the Journal of the American Medical Association, have suggested that most of us should just take a daily multi-vitamin/multi-mineral supplement and be done with it.  In fact, here at PN, we also recommend multi-vitamins.

However, I’ve got to be honest. This is just a half measure.

Truthfully, the absolute best course of action is to focus on bringing nutrient rich whole foods back into our diets.  In essence, we’ve got to focus on eating more high quality food.   Only then are we assured to get that mother-nature designed bounty of synergistic nutrients – vitamins, minerals, and phytochemicals – in every last bite.

Improving your diet

If you’re looking for the ideal system to do just that – to introduce phytochemical-rich, micronutrient-rich foods into your diet – in a way that’ll help you improve your health, appearance, and performance – let us help.

Over the last 10 years, we’ve helped over 50,000 clients transform their bodies and their lives through eating better and exercising properly.  And with our Precision Nutrition System, we’ll teach you exactly what you can do – immediately – to build a healthy, lean, high-performance physique in record time.

Learn more

To learn more about making important improvements to your nutrition and exercise program, check out the following 5-day video courses.

They’re probably better than 90% of the seminars we’ve ever attended on the subjects of exercise and nutrition (and probably better than a few we’ve given ourselves, too).

The best part? They’re totally free.

To check out the free courses, just click one of the links below.