Low oxygen levels related to fatigue can involve several biological systems working together: air movement through the lungs, oxygen transfer across the lung surface, hemoglobin-based oxygen transport in red blood cells, blood circulation through the heart and vessels, tissue oxygen delivery, mitochondrial oxygen use, and antioxidant protection. Oxygen is required for oxidative phosphorylation, the mitochondrial pathway that produces most cellular ATP. When oxygen delivery or oxygen use is inefficient, fatigue can develop because cells have less capacity to maintain normal energy production. This pattern can be influenced by shallow breathing, poor circulation, low iron intake, low folate intake, reduced antioxidant status, oxidative stress, inflammation, dehydration, electrolyte imbalance, airway irritation, poor endothelial function, and reduced mitochondrial efficiency. Hemoglobin requires iron, while red blood cell formation depends on folate, vitamin B6, copper, and other nutrients. Blood vessel function is influenced by nitric oxide signaling, potassium balance, magnesium balance, oxidative stress, and inflammatory signaling. Mitochondria depend on oxygen, B vitamins, minerals, amino acids, and antioxidant systems to support normal electron transport and ATP production. Plant-based support focuses on foods that provide nitrate-rich vegetables, vitamin C-rich fruits, iron-containing legumes and greens, folate-rich greens and beans, magnesium-rich seeds and leafy vegetables, potassium-rich fruits and vegetables, antioxidant-rich berries, carotenoid-rich orange vegetables, polyphenol-rich herbs and teas, and fiber-rich foods that support gut microbiome and SCFA signaling. Beetroot, spinach, arugula, kale, watercress, romaine lettuce, and celery provide dietary nitrates and minerals that support nitric oxide biology and vascular tone. Beans, lentils, chickpeas, pumpkin seeds, sesame seeds, spinach, and whole grains provide plant iron and related cofactors. Citrus, kiwi, bell pepper, broccoli, berries, and pomegranate provide vitamin C and flavonoids that support antioxidant defense and improve non-heme iron absorption when eaten with iron-rich plant foods. Sweet potato, carrot, pumpkin, kale, and spinach provide beta-carotene and related carotenoids that support epithelial and antioxidant biology. A P53 Nutrition approach keeps the pattern 100% whole-food plant-based: no oils, no meat, no dairy, and no toxins. The goal is to support oxygen transport biology, vascular function, hydration, mitochondrial energy pathways, and antioxidant defenses through whole plant foods only.