Calcium and Phosphorus Explained | Bone Health, Blood Calcium, Bioavailability, and Major Minerals

Welcome back to the Pre-Health Science Explainers series for pre-health science students, including future nursing students, pre-med students, pre-dental hygiene students, pre-radiology students, pre-EMS students, pre-chiropractic students, and other allied health professionals. In this lesson, we continue our water and major minerals playlist by focusing on calcium and phosphorus, the two most abundant minerals in the human body. These major minerals provide the structural foundation for bones and teeth, but they also support many essential functions beyond the skeleton. You will learn why calcium is the most abundant mineral in the body and why about 99% of it is stored in bones and teeth. Calcium helps form hydroxyapatite crystals, which give the skeleton strength, while the small amount of calcium in the blood supports muscle contraction, nerve signaling, and blood clotting. This video also explains how the body tightly regulates blood calcium levels. When blood calcium drops too low, parathyroid hormone, vitamin D, the kidneys, intestines, and osteoclasts work together to raise calcium levels. When blood calcium rises too high, calcitonin and osteoblasts help move calcium back into bone. We also explore calcium food sources and bioavailability. Dairy foods, fortified foods, and low-oxalate greens such as kale and bok choy can provide calcium, while spinach contains oxalates that bind calcium and greatly reduce absorption. You will also learn why calcium needs are especially high during adolescence, when the body is building peak bone mass. Finally, this lesson introduces phosphorus as calcium’s essential partner. Phosphorus supports bones and teeth, ATP production, DNA structure, cell membranes, and pH balance. The video also compares deficiency and toxicity concerns for both calcium and phosphorus, including osteopenia, osteoporosis, kidney stones, soft tissue calcification, and the connection between phosphorus toxicity and chronic kidney disease. In this video, you will learn: • Why calcium is the most abundant mineral in the body • Why 99% of calcium is stored in bones and teeth • What hydroxyapatite crystals are • How calcium supports muscles, nerves, and blood clotting • What hypocalcemia and hypercalcemia mean • How parathyroid hormone raises blood calcium • How vitamin D supports calcium absorption • How osteoclasts and osteoblasts affect bone remodeling • How calcitonin helps lower blood calcium • Major food sources of calcium • What calcium bioavailability means • Why low-oxalate greens can be good calcium sources • Why spinach calcium is poorly absorbed • Why adolescents need more calcium • What peak bone mass means • Why phosphorus is essential for ATP, DNA, cell membranes, and pH balance • How calcium and phosphorus imbalances affect health This video is ideal for students taking Human Nutrition, Biology, Healthcare Science, Public Health, Nursing prerequisites, Allied Health coursework, and nutrition science courses. It is also helpful for students preparing for the TEAS, HESI, ATI, MCAT, and other healthcare entrance exams. If you are looking for clear and student-friendly explanations of nutrition science, major minerals, bone health, electrolyte balance, metabolism, and human biology, subscribe for future explainers in this series. This video is intended for educational purposes only and does not provide medical advice, diagnosis, or treatment. Please consult a qualified healthcare professional for guidance related to your individual health, medications, or supplement use. Timestamps 0:00 Introduction to calcium and phosphorus 0:17 Calcium as the most abundant mineral 0:36 Calcium in bones and teeth 0:45 Lesson roadmap 1:03 Calcium functions 1:12 Structural role of calcium 1:21 Regulatory role of calcium 1:39 Blood calcium regulation 1:48 Calcium balance as a thermostat 2:14 Hypocalcemia and hypercalcemia 2:33 Parathyroid hormone, or PTH 2:45 Osteoclasts and bone breakdown 2:54 PTH, vitamin D, kidneys, and intestines 3:06 Calcitonin 3:16 Osteoblasts and bone building 3:31 Calcium food sources 3:45 Dairy sources of calcium 3:50 Low-oxalate greens 4:00 Fortified foods 4:06 Calcium bioavailability 4:24 Calcium absorption from dairy 4:30 Calcium absorption from low-oxalate greens 4:42 Oxalates in spinach 4:57 Calcium needs 5:12 Peak bone mass 5:37 Phosphorus 5:46 Phosphorus as the second most abundant mineral 6:01 Phosphorus functions 6:03 ATP and energy 6:08 DNA and cell membranes 6:11 Phosphorus and pH balance 6:19 Calcium and phosphorus imbalances 6:30 Calcium deficiency 6:40 Calcium toxicity 6:44 Phosphorus deficiency 6:52 Phosphorus toxicity 7:00 Phosphorus toxicity and chronic kidney disease 7:16 Diet, calcium, and weight-bearing exercise 7:32 Preview of sodium, potassium, and chloride Hashtags #Calcium #Phosphorus #BoneHealth #MajorMinerals #NutritionScience