Usual disclaimer: no one can provide specific medical advice for a person or condition without an in-person interview and physical examination, and a review of the available medical records and recent and past testing. This comment is for general information purposes only, and not intended to provide medical advice. No physician-patient relationship is implied or established.True nutritional deficiencies are almost unheard of in modern first-world countries. They are either the result of very restrictive diets, or of medical conditions that cause problems with the absorption of nutrients, such as inflammatory bowel disease or celiac disease, or surgery of the gastrointestinal system, such as bariatric surgery (weight-loss surgery) or removal of parts of the small intestine (usually due to injuries like getting stabbed or shot in the abdomen).As an aside, there is an "epidemic" of vitamin D deficiency currently. I use the quotation marks, as this is a controversial issue. By some measures, up to 60% of people in the United States are "deficient" in vitamin D. However, it is possible that the values that are considered to be sufficient are just wrong. For an interesting discussion of how this came to be you can read this interesting article about the physician who more-or-less singlehandedly creates the modern idea of vitamin D deficiency.https://www.nytimes.com/2018/08/18/business/vitamin-d-michael-holick.htmlIt should be noted that there are studies that associate vitamin D deficiency with worse outcomes of various illnesses, including COVID-19, but that large studies of vitamin D supplementation have never shown any benefits whatsoever.Finally, and to me mysteriously, despite the "epidemic" of vitamin D deficiency, children are oddly spared the effects: vitamin D deficiency in children produces a specific syndrome called rickets, which is very nasty, but somehow, there is essentially no rickets in the United States. The only case I ever saw was a well-meaning but utterly misguided family feeding their newborn infant home-made vegan formula.
How do you know if you're nutritionally deficient in some way?Male. Late 20s. Non smoker. Non drug user. Non drinker.So I have a fairly basic diet. I eat a reasonably healthy mix of meat veg and fruit every day. But it is basically the same things every day. So unless there is a major health issue as a symptom is there a way to know if there's something else I need to be eating?For example I can't eat fish/ seafood. Is there a symptom that I should mindful of that means I'm missing something from my diet that fish/ seafood would normally provide?