According to me, just about everybody. Due to modern farming methods, food ain't what it used to be. Dammit, even nostalgia ain't what it used to be! Due to changes in lifestyle:-
a) Most people are more sedentary than they used to be. This means that they require less food than they used to in order to not get fat. Less food, coupled with less nutrients in the food = dietary deficiencies.
b) Most people don't get as much sun on their skin as they used to, as they now work, play & live mostly indoors and when they do go outside, they are encouraged to Slip Slop Slap (slip on a shirt, slop on sunscreen and slap on a hat). This results in hypovitaminosis D, as only an Eskimo's diet contains enough dietary Vitamin D. The RDA of 200/400/600iu/day (depending on age) is woefully inadequate and totally out of touch with modern research.
c) Most people don't eat much oily fish. Also, animal & vegetable produce now contains more omega-6 & less omega-3 than it used to. This can result in a large imbalance. I eat a 120g can of sardines in tomato purée most days. This also provides protein, lycopene from the tomato purée and calcium from the soft bones.
d) Diets low in dark green vegetables & fruits lack Magnesium & Potassium.
e) Diets low in fermented products lack Vitamin K2.
I currently supplement with:-
400mg/day of Magnesium, as 4g/day Epsom Salts.
5,000iu/day of Vitamin D3.
I also use Lo Salt, which contains 2 parts Potassium to 1 part Sodium.