DEAR DR. BLONZ: Being a nut lover, I have a question after your recent column on the topic. Your information stated that nuts in their shells would keep for about six to 12 months if stored in a cool, dry place, but that shelled nuts only keep about half as long. I recently discovered an unopened 26-ounce container of lightly salted peanuts in the back of my kitchen pantry. The best-by date on the bottom was 2/26/2017, which means it is three years out of date. I assumed they would taste stale or whatever, but figured I’d give them a try. I recently opened it and found the taste and texture seemed like a brand-new container, fresh off the store shelf. The thing I do not know is whether the passage of time has affected the nutrients. Any thoughts? -- A.F., via email

DEAR A.F.: There are different methods of quality-control dating for foods. Different types of dating provide information on a range of issues, including a food’s loss of quality, the risk of microbial spoilage, and an increased risk of foodborne illness. (Check the information in an earlier column: blonz.org/we3wt.)

Nuts tend to use the “best if used by” type of freshness date, providing a date after which the contents would be expected to decrease in flavor and quality. The wild-card aspect is that one can’t accurately predict the lifespan for every product. The dates typically have a bit of a buffer, but three years seems like pushing it. My general advice is to toss out-of-date foods under the canon of “Why take a chance?”

You have sampled from that container and have found nothing wrong. Given that the peanuts show all signs of being unspoiled and edible, I would predict they would also still be nutritious. Oxidation is the main type of spoilage affecting nuts, occurring when nuts are in contact with the oxygen in the air. Vacuum-sealing keeps air away, so it limits this process. The nuts, however, continue to age as they are stored. They might taste and smell fine when first opened, even if their freshness date is history, but that quality will drop more rapidly in a long-stored package than in a container opened within its freshness period.

Fats are the most prevalent nutrient in nuts, and these suffer during oxidation. It is the short-chain fats that take the hit first. While there are not many of these in peanuts, when the nuts do turn, it makes them no longer pleasant to eat or smell. There will be an effect on some nutrients, especially those that act as antioxidants; it’s their job to react with oxygen, thereby protecting oxidizable substances such as fats.

Again, I do not advise eating out-of-date foods, but if you are going to continue eating from this particular container, consider storing it a well-sealed container in the refrigerator or freezer, as cold temperatures also help slow oxidation and other types of spoilage.

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: 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.