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.

DEAR DR. BLONZ: I’m on a medication (spironolactone) that is to be taken with food so as to not upset my stomach. I’m not an early-morning eater. Does a good-sized banana plus coffee satisfy that requirement? Thanks -- C.L., Richmond, California.

DEAR C.L.: The “with food” recommendation can be for various reasons, such as when a particular type of food facilitates absorption, or if food limits stomach irritation if the medication were to sit in direct contact with the stomach lining. It depends on the drug and the health situation involved. There should be information provided with the prescription, or you could ask the prescriber or your pharmacist what “with food” would mean for that particular medication. This allows you to speak with professionals who can consider any other medications or health conditions you are being treated for.

You provided the name of your medication (spironolactone); that is one that can irritate the stomach lining, so the presence of food would limit that unwanted effect. As to whether your banana and coffee would suffice, that really depends on how your body responds. Be aware that coffee on an empty stomach can be an irritant in its own right. A small amount of protein and fat may help here, but you and your health professional will be the final arbiters. For more on spironolactone, see b.link/mdii2b2e.

DEAR DR. BLONZ: I see recommendations to drink hot water first thing in the morning on an empty stomach for its “many metabolic benefits.” The list includes detoxification and digestion because hot water can stimulate blood circulation and the lymphatic system to flush toxins from the body. Sounded too good to be true, but the poster cites the Journal of Neurogastroenterology and Motility (2010) for support. This would be so easy to do if it worked. There is no money to be made from hot water, so why would one post such information if it were false? Is there anything to this? -- F.P., Oakland, California

DEAR F.P.: Those claimed benefits from drinking hot water first thing sound too good to be true? Precisely! Social media is set up to reward blatant nonsense, as wacko posts encourage people to engage and criticize, and the conversation begins. You may find defenders of the silly stuff and wonder what that’s all about. Those defenders can be secondary identities of the original poster, all designed to increase the number of posts. Viral conversations can result in financial rewards for the posters of falsity. Don’t get conned by the blatant run of health nonsense on social media.

Finally, I found the citation referenced in that hot-water post. It does not support the claims; rather, it concerns the use of hot water by people with a specific swallowing disorder. It is not uncommon for misinformation promoters to make things up and falsely cite research. Always check with evidence-based resources. Irrespective of whether this has anything to do with your interest in this topic, be aware that swallowing disorders are nothing to be trifled with. For more on this topic, see the article at b.link/n82uxzp.

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.