Common nutritional deficiencies in modern diets include vitamins D and B12, iron, iodine, and omega-3 fatty acids. Many individuals do not consume adequate amounts of these essential nutrients due to factors like processed foods and limited dietary variety. Vitamin D deficiency can lead to bone health issues, while B12 deficiency may cause neurological problems. Iron deficiency often results in anemia, causing fatigue and weakness. Improving dietary habits by incorporating a broader range of whole foods can help mitigate these deficiencies and promote better overall health.