Questions from Listeners: April 2022 Edition

Will eating before exercise ruin the benefits? Will a collagen shake boost your recovery? Is expensive olive oil worth the extra money? Could my supplements be causing my A-fib? Nutrition Diva has answers to these and other listener questions.

Monica Reinagel, MS, LD/N, CNS
6-minute read
Episode #662

Should you fast or fuel before exercise?

Long time listener Rohini writes:

Q. I have been trying to do intermittent fasting for the past few months and can manage a 14 hour fast quite comfortably (8 pm till 10 am). I almost always exercise earlier in the morning. But I start to feel tired fast if I haven't eaten something. Intermittent fasting experts often tout the benefits of exercising in a fasted state but other credible sources insist on eating first before exercising! What do we morning exercisers do?

A. Even after an overnight fast, you should have more than enough fuel on board for a moderate-intensity workout. That said, the benefits of fasted exercise are often exaggerated. The real key here is what makes you most comfortable because that will support more consistent exercise. In the long run, that's far more beneficial than the incremental gains that you might get from following someone's arbitrary rules about pre-workout fasting or fueling.

Is Evening Primrose Oil effective for fibrocystic breasts?

Val writes;

Q. Recently my doctor told me to start taking Evening Primrose and vitamin E for fibrocystic breast disease. However, I can't seem to find studies that support using Evening Primrose for either breast pain or decreasing the nodule size. In fact, the NIH says:
"studies of Evening Primrose Oil for breast pain have not found it to be more effective than a placebo." What's your take?

A. There have only been a limited number of studies on EPO and benign breast disease. One study found that it was not more effective than a placebo. (Actually, the study found that it was SLIGHTLY more effective than placebo but didn't reach the threshold for statistical significance.) But other studies have found that it was as effective as prescription drugs that are sometimes prescribed for this condition. Then again, the prescription drugs aren't slam dunks, either. A significant number of people don't find them helpful.

Seeing as EPO has few side effects or safety concerns, your doctor may reason that it's worth a trial-of-one to see if you are one of the people who does see an improvement. I can see the logic in that.  If you do decide to try it through, make sure you're taking enough of it (usually, 6 500 mg capsules a day) and for long enough (8-12 weeks) before you decide whether or not it's helping.

Which is better: whole oats or oat bran?

Stephen writes:

Q. Several health-related websites state that oat bran is superior to rolled oats, but I often hear that whole grains are important to health. I eat plenty of other whole grains (wheat, corn, and rice) and am largely vegetarian. Does isolating the bran from oats (or even wheat) remove significant benefits?

A. I think it's more accurate to say that isolating the bran from oats or wheat concentrates the benefits that you get from the fiber. It's the soluble fiber in oat bran, for example, that's largely responsible for its modest cholesterol-lowering effects. Fiber is not the only benefit we get from whole grains. But it is a significant one. If you ate only bran, you'd be missing some of the nutrients that are concentrated in other parts of the whole grain—some of the B vitamins, for example. But because you eat plenty of other whole grains, this wouldn't seem to be an issue for you. So, I don't think you're missing anything important by choosing oat bran instead of whole oats.

Does collagen boost athletic performance?

Affifa writes:

Q. Lately, I have been seeing a lot of workout shakes that feature collagen as a way of enhancing performance. I always associate collagen with skin and aging. How does collagen help with working out?

A. Collagen is a source of protein, which can help with workout recovery by boosting muscle protein synthesis. But it's actually not a terribly high-quality protein source. In fact, its relatively low protein quality sets it apart from most animal-based protein sources. 

Most of the claims for collagen as a performance-boosting supplement seem to be made by people selling collagen supplements. Meanwhile, researchers have found that whey protein, which is significantly less expensive, is actually more effective at boosting muscle protein synthesis and workout recovery.

What's the safest kind of refined olive oil?

Chloe writes:

Q. I’ve been trying to find out more information on the safest kind of refined olive oil. I don’t like the idea of chemicals being used, but perhaps it sounds worse than it is. Since there is a big price difference, I’d love to know whether I need to buy more expensive stuff or whether I’m wasting my money.

A. Hexane is a chemical that's often used to refine oils and this method is far less expensive than other mechanical processes. Like anything else, hexane can be toxic if you are exposed to enough of it. However, hexane is also an extremely volatile compound. That means that virtually none of it remains in the refined oil. Gasoline fumes in the environment actually account for 50 times more hexane exposure for the average consumer than all food sources combined. And after almost 100 years of use, no adverse health effects from hexane-refined oils have ever been detected. 

However, here is an interesting and somewhat counter-intuitive finding about unrefined olive oil:

Refining removes impurities from oil, which generally increases their smoke point. Unrefined (or extra virgin) olive oil, for example, has a smoke point of about 375 degrees F. Refined (or light) olive oil has a smoke point of 465 degrees F or so.

Although it does not have the highest smoke point, extra virgin olive oil turns out to be one of the best choices for high-heat cooking, based on its superior ability to resist oxidation, as well the low formation of harmful compounds. In tests, extra virgin olive oil was actually more stable than light or refined olive oil, perhaps because it is higher in antioxidants. (Those same antioxidant compounds, by the way, are a big factor in the characteristic aroma and flavor of really high-quality olive oil.)

Could herbal supplements be causing my A-fib?

Janet writes:

Q. I recently experienced some episodes of atrial fibrillation. When visiting with my cardiologist, she said that my supplements could be causing my A-Fib. Are there supplements that have the side effect of increasing irregular heartbeats?

A. Yes, some nutritional and herbal supplements can cause an irregular heartbeat. Examples include valerian, hawthorn, ginseng, and ephedra. In addition, nutrients such as potassium, magnesium, or vitamin D can cause arrhythmia when consumed in excessive amounts.

We tend to think of nutritional and herbal supplements as safe because they are natural or food-based. Keep in mind that plants that are used as herbal medicines can sometimes have quasi-pharmacological effects on the body. That's how they became known as medicines! And most nutritional supplements contain nutrients in far higher concentrations than you would ever get from food. It's surprisingly easy to overdo it, especially if you're taking a few different supplements that may contain some of the same nutrients. Finally, nutritional supplements can sometimes interact with prescribed medications in ways—either increasing or decreasing their potency.

Just because you don't need a doctor's prescription for them, it doesn't mean that nutritional and herbal supplements are harmless. If you take supplements, I would suggest that you review all your supplements (including dosages) with your cardiologist, family doctor, or (best of all) your pharmacist.

How much vitamin D does it take to correct a deficiency?

Barb writes:

Q. I saw three doctors this week and got three different answers about taking vitamin D. I have been taking it for years but a recent blood test showed I have low vitamin D. My GP wants me to up the intake to 15,000 IU. My cardiologist thinks that's crazy and I should expose my belly and butt daily to the sun because no one gets skin cancer on their butt or belly. My dermatologist thinks both ideas are nuts but did not offer any alternatives. What's your take?

A. Of the three, I think your GP is actually the least crazy. The cardiologist's recommendation doesn't seem very practical; we don't want you arrested for indecent exposure, after all. And sometimes it can take very high doses of oral vitamin D to restore optimal blood levels. This is definitely something that you'd want to do with a doctor's supervision so that she can monitor the effects and adjust as needed. One cool thing about vitamin D is that you don't have to take it every day. It can also be taken in higher amounts on a weekly or even monthly basis.

And, of course, a bit of sunshine on your exposed skin can also be a big help in boosting vitamin D.  If you're worried about skin cancer, just make sure that you apply sunscreen well before your skin starts to turn pink.

About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.