DEAR DR. BLONZ: I am interested in the health benefits of plant phytochemicals, and you include chocolate among them. Are the phytochemical antioxidants in the cocoa powder or in the cocoa fat? If they are in the fat, does that mean the only way to get the benefits is to eat full-fat chocolate? -- M.D., Raleigh, North Carolina

DEAR M.D.: Successful plants evolved the ability to capture energy from the sun, using it to fuel the construction of their complex structures and substances and power all aspects of their metabolism. (We rely on the foods we eat to provide our energy.) But, aside from serving as an essential source for energy, the sun's rays can have devastating effects on living tissues. Similar to the visible effects of sunlight bleaching colors, excessive exposure to the sun's oxidizing rays can damage tissues and cause cancer.

While animals develop skin adapted to their habitats, they can move and find shade and shelter. Plants remain anchored by their roots; successful ones have evolved appropriate defenses for every stage of their life cycle. The most straightforward protections are shields in the form of opaque barriers. Examples in nature include leaves and seed coverings. We rely on hats, umbrellas and sunscreen applied directly to protect our skin, but critical are the antioxidants that can inhibit oxidative damage to body tissues and substances. We find antioxidants and other protective phytochemicals in the fruit and leaves that are exposed to the environment. Likewise, plants that tend to have higher levels of fats and oils will usually have lipid antioxidants on call.

Most basic to this discussion is an appreciation that phytochemical protectants are there for the plant's benefit, not ours! Every plant has evolved its own protection strategy, underscoring the wisdom of including a variety of plant-based foods in the daily diet. It is only when such foods are a regular part of what we are eating that they can be there to work their magic for us when needed. For more on antioxidants, see b.link/tb55h26.

As you pointed out, research on chocolate has identified its variety of beneficial compounds. The primary antioxidant phytochemicals in cocoa beans are the flavonols, a type of flavonoid found in the solid fraction of chocolate. These are in the cocoa powder and, of course, in the whole chocolate confection. Dark chocolate tends to contain more than milk chocolate, with white chocolate containing little, if any. As for whether having cocoa powder is a better way of getting the benefits of the chocolate, that, I think, is a matter of personal preference. For more on the benefits of chocolate, see b.link/m7wkbxs.

There are plenty of foods with wonderful attributes. Eat chocolate, not because it is prescriptive, but because you enjoy it.

Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: It is now crab season on the West Coast, one of my favorite periods. When I clean the crabs myself, there is always this squishy stuff under the shell, called crab butter. There are mixed opinions on this substance. I have used it in my dipping sauce to add flavor, but this practice was criticized by recent guests where it was on the table. Is crab butter bad for health? Thank you. -- J.B., Santa Clara, California

DEAR J.B.: Like you, I also look forward to the arrival of crab season. That "crab butter" you refer to is the yellow-white-greenish substance that is revealed after the large shell has been removed. This is actually a digestive gland known as the hepatopancreas, the crab's equivalent of a combination liver and pancreas. This organ has a mix of functions for the crab, producing digestive enzymes, filtering impurities from its equivalent of blood and providing some energy storage.

There would be little risk to us if the crab on your plate had spent its entire life in pristine waters, but crabs do not come with passports to check where they've been hanging out. If the crab has spent time in areas with oil spills, agricultural runoff, PCBs or exposure to toxins or heavy metals, there is a proportionally greater risk of accumulation in its internal organs, with its hepatopancreas bearing the brunt. There is also a greater risk of toxin accumulation during algal blooms, as domoic acid forms, and this is a dangerous neurotoxin. Crab seasons get adjusted for public safety to avoid these blooms.

For more on domoic acid, see the article at b.link/drd4vfb. Consider the red flag to be that while some refer to this as crab butter or crab mustard for its taste, it's also called crab poop for the other stuff you don't want. Best to stick with the meat and make your own crab butter.

DEAR DR. BLONZ: I add various dried berries to my cereal every morning, but a friend told me that dehydrated berries no longer have antioxidant value. Can you comment on this? -- R.B., Pinole, California

DEAR R.B.: Dried berries, such as blueberries, cranberries, currants, raspberries and cherries, all have considerable nutritive and antioxidant value. I have no idea where your friend got that misinformation. Similar to you, my go-to breakfast is berries, fresh, frozen or dried, with high-fiber whole-grain granola and unflavored, full-fat yogurt. I opt for organic when available. It's a great way to start the day, giving you a leg up on healthy eating.

Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: There have been periods in history, such as the Irish potato famine, when people had to survive with limited access to food. I follow a healthy, varied diet, with organically grown produce preferred when available. I avoid heavily processed foods. My question is: If humans can survive periods when they don't get all their requirements, are daily nutrient requirements necessary? -- T.S., Raleigh, North Carolina

DEAR T.S.: We can survive periods of inadequacy through the human organism's evolved ability to recycle nutrients when intake is deficient. This is not a 100% reliable process, as it depends on the nutrient involved and on potential complications, such as infection, illness or stress. This ability can be lifesaving in the short term, but that would be merely surviving, not thriving. For an informative article on human diet evolution, see b.link/fh5ukwc.

Essential nutrient levels are affected by the efficiency of absorption, the rate of excretion, and whether and how a particular nutrient gets stored, retrieved from storage and recycled if needed. These elements can adjust as short-term adaptations to a low intake, but prolonged deficiencies result in a drain on availability, with impacts on systems that rely on their presence. Quality of life is also affected by a limited nutrient reserve.

So, assuming there is air to breathe and water to drink, we can last without any food for a month or so, depending on our age, initial state of health, the amount of body fat (spare energy) present and the environment in which the deprivation takes place. (A "you call that living?" descriptive might be appropriate here.) Adding calories can help a bit, but it is limited without the needed raw materials and essential nutrients. The evidence supports the wisdom of daily nutrient intakes.

Nutrient requirements were first developed in the 1940s during World War II, when effective rations for soldiers had to be formulated. The first index was the minimum daily requirements (MDR). This was a measure of the minimum amounts of protein, vitamins and minerals to prevent a deficiency or other metabolic malfunction correctable by providing the deficient nutrient.

This was calculated by dividing the amount stored in the body by the number of days of zero intake it would take for the body to show signs of a deficiency. Consuming the MDR could effectively prevent such a deficiency. But this was measured in young individuals in excellent health, meaning they had no medical issues or medications. We have learned how various health conditions and medications affect nutrient requirements.

Since then, we have moved to recommended dietary allowances (RDAs) -- no longer using "daily" in the name. This is considered the average daily intake to satisfy the needs of up to 98% of healthy individuals. You don't need to meet every nutrient requirement every day, but as our health is involved, why mess?

You raised the topic of the Irish potato famine. This terrible event was made possible through that culture's primary subsistence on potatoes, with bits of dairy and fish. Their narrow focus exploded into tragedy following a blight that affected the potato crop, resulting in seven years of starvation, disease and emigration. Check b.link/2vphwvh for more on the Irish potato famine.

Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.