DEAR DR. BLONZ: This may seem like an odd question for someone who writes about nutrition, but how long can a body go without food? A close friend recently experienced a loss, which has caused her to suffer a hard emotional blow. She says that she has no appetite. She hasn’t been able to eat anything; when she tries, it results in nausea and her body’s rejection of the food.

As would be expected, she has lost a lot of weight lately, and doesn’t look healthy to me. -- F.S. San Jose, California

DEAR F.S.: My sincere sympathy to your friend, and any affected by the loss. Grief can affect the body in many ways, and while a loss of appetite can be one of them, overeating, ironically, can be another. For more on the body’s reaction to grief, visit b.link/ncbi58.

Addressing your question: Our body is designed to avoid waste, so we shift gears to handle food whenever it’s consumed. But if nutrients are not provided for an extended period, a sophisticated series of adaptations takes place to pare down the unnecessary use of energy and loss of essential resources. While we may be conscious of why we are no longer eating, the systems in our body are not in that loop.

One adaptation is a scaling-back of the metabolic efforts involved with digestion, which might explain that queasiness or nausea your friend experiences when food is reintroduced. The discomfort tends to pass, but reintroducing food in this scenario should be done gradually, relying on plant foods such as juices, soups, fruits and cooked vegetables.

A lack of food also causes a slowing of the metabolic rate, which brings about a lowering of body temperature. There will be less circulation near the skin surface, which is one of the reasons why people who go without food are easily chilled and may have a sallow look about them.

Friends and family serve as an invaluable source of support, but an inability to eat lasting for days suggests some professional assistance may be needed. In the meantime, given that the body requires more water than any other nutrient, encourage your friend to consume fluids -- even something like a sports drink, which provides not only fluids, but also electrolytes and calories. To emphasize this important point: We can last only a few days without water.

The human body can survive for many weeks without food, but much depends on one’s state of health and the amount of excess energy (i.e., body fat) at the start. I hope that your friend finds the strength to work through her grief, and is spared any testing of the limits of her endurance.

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: We are feeling lots of joy from our daughter’s recent marriage, and we just learned that they have plans to start a family. We set a good example of healthy eating and an active lifestyle, but have been thinking about encouraging her to begin taking a supplement to provide more B vitamins, especially folate. Before doing so, I wanted a reasonable argument to support my case. I am hoping that you might be able to help. -- G.P., Scottsdale, Arizona

DEAR G.P.: Congratulations and best wishes to your daughter and her new partner. The diet and lifestyle example you have set will prove to be persuasive, but you ask about folate, so let’s look at what gives this nutrient its status with child development.

Our bodies are constantly being broken down and remade; whatever can be reused, is. If we could check the passport of an essential amino acid, for example, we would probably find notations that it had been part of hormones, enzymes and disease-fighting antigens, as well as various organs and tissues.

Folate, also called folic acid, is integral to the body’s construction mechanism, moving around single carbon “bricks” as needed. Folate is also essential for the synthesis of DNA and RNA, the genetic material involved in cell division and reproduction. That’s quite a dance card.

One of the first places to reflect a folate deficiency is the blood, as our doughnut-shaped red blood cells have a relatively short lifespan. If there’s insufficient folate, red blood cells get improperly constructed, resulting in a type of anemia. Resupplying the needed folate will bring about a dramatic recovery in those suffering from folate-deficiency anemia.

But a folate deficiency isn’t as easily solved during pregnancy. Following conception, various bodily systems begin to develop, and this involves a massive expansion of “construction projects.” One of the first systems to develop is the fetal nervous system, including the spinal cord and the bony column that protects it. Adequate folate must be present during the first few weeks after conception for this process -- but during this time, a woman might not yet be aware that she is pregnant. If the body is folate-deficient during this period, it can lead to mistakes in the formation of the nervous system, and unfortunately, no amount of folate can correct such problems after the fact.

Spina bifida is a congenital disability in which one or more of the vertebra of the spinal column fails to develop properly. It affects approximately 1 out of every 1,000 babies born, and as much as 75% of all cases of spina bifida are attributable to a folate deficiency during those first few weeks of pregnancy. This makes it especially important for women to have adequate folic acid before pregnancy even begins.

The problem is that less than half of all pregnancies in the United States are planned. The U.S. Public Health Service recommends that all women of childbearing age who are capable of becoming pregnant should consume at least 400 micrograms of folic acid per day. The requirement rises to 600 micrograms during pregnancy, and drops to 500 micrograms during breastfeeding. Good sources of folate include legumes, vegetables (especially leafy greens and asparagus), citrus fruits, eggs and various fortified foods.

Best to you and your potentially expanding family.

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’ve heard from certain sources that pecans have about 19 nutrients, and peanuts only nine. Could you help me further by giving me a list of nuts and their nutrients? Please let it include almonds, pecans, walnuts, Brazil nuts, peanuts and macadamia nuts. -- J.L., Tulsa, Oklahoma

DEAR J.L.: I am also a nut advocate, having them nearby at work and home. A couple of issues up-front: First, I will be using “nuts” or “seeds” to refer to nuts, seeds, drupes and peanuts, which are legumes. Second, we often find the presence of an assortment of nutrients in certain foods, but that does not mean there’s going to be enough in a typical serving to impact our nutrition. For example, an herb such as oregano has a host of nutrients and phytochemicals, but only in micro quantities, as far as our consumption goes. They are there for the sustenance of the oregano plant, and will not make much of a dent in human requirements.

Back to your question: The information you request is in a recent book I authored for the University of California, Berkeley’s Wellness Letter, which is available online at no charge. The intent was to create a supermarket shopping guide that goes up and down the aisles, telling you what to eat and why. There is a chapter on nuts, and I list their respective standout nutrients. Check it out at b.link/nuts14. The coverage also includes a discussion of nut butters, allergies, storage issues and buying tips.

Why is it that nuts are so high in fat? Plant structures are made from carbohydrate, which is relatively low in energy and mostly water by weight. Nuts and seeds, by contrast, are primarily fat -- nature’s most concentrated form of energy.

This makes perfect sense from the plant’s perspective. Unlike animals, plants produce their own energy from the sun, but this won’t begin until the rays of the sun penetrate their leaves. The only way a seed can gain entry to the energy-production game is to have its own leaves. That means having a concentrated source of energy on hand to fuel the sending out of a taproot to bring in water, and the sending up of a shoot to develop into leaves to open into the sun. Once that is operating, the plant uses the energy from the sun to make carbohydrate structures, as this allows the most growth for the energy investment.

The logic here is that the successful plants are the ones that can grow above their neighbors, getting their leaf surfaces into the sun to continue making energy. This shifts, of course, when it’s time to produce seeds for the next generation.

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.