Creatine is a well-researched dietary supplement commonly used to improve exercise performance and increase muscle mass. It is naturally found in the body, primarily in skeletal muscle, and also in foods like red meat and seafood¹².

Benefits of Creatine

1. Athletic Performance: Creatine is widely recognized for its ability to enhance exercise performance, particularly in activities requiring short bursts of high intensity, such as weightlifting, sprinting, and high-intensity interval training²³.
2. Muscle Strength and Mass: Supplementing with creatine can improve muscle strength and promote muscle growth. It is particularly effective in younger and older adults when combined with resistance training³.
3. Neuroprotective Effects: Emerging research suggests that creatine might have neuroprotective properties, potentially benefiting conditions like neurodegenerative diseases⁴.
4. Age-related Muscle Loss: Creatine supplementation can help improve muscle strength in older adults, particularly when combined with exercise³.

Side Effects of Creatine

1. Gastrointestinal Distress: Some individuals may experience stomach ache, nausea, or diarrhea, especially with higher doses of creatine⁵⁶.
2. Weight Gain: Creatine often causes weight gain due to water retention in muscles⁴. This is usually a temporary increase and can be beneficial for muscle growth.
3. Renal and Hepatic Function: Despite anecdotal reports of kidney and liver dysfunction, well-controlled studies have not found significant adverse effects on renal or hepatic function in healthy individuals using recommended doses⁷⁸.
4. Mood and Anxiety: Some studies have reported changes in mood and anxiety levels in a small number of individuals⁹.

Safety of Creatine

Overall, creatine is considered safe for use by healthy individuals, including athletes, when taken at recommended doses (typically 3-5 grams per day). Long-term studies indicate that it does not lead to significant adverse health effects⁸¹⁰. However, those with pre-existing kidney or liver conditions should consult a healthcare provider before starting supplementation.

Footnotes

1. MedlinePlus ↩

2. Examine.com ↩ ↩²

3. MedlinePlus ↩ ↩² ↩³

4. PubMed Central ↩ ↩²

5. PubMed ↩

6. PubMed ↩

7. PubMed ↩

8. PubMed ↩ ↩²

9. PubMed Central ↩

10. PubMed ↩

Benefits of Vitamin D

1. Bone Health: Vitamin D is essential for calcium absorption in the gut and maintaining calcium and phosphate levels to support normal bone mineralization¹. It helps prevent rickets in children and osteomalacia in adults¹.
2. Immune Function: It modulates the immune system, enhancing the pathogen-fighting effects of monocytes and macrophages².
3. Cardiovascular Health: Some studies suggest that vitamin D may help reduce the risk of cardiovascular diseases by influencing blood pressure and cholesterol levels³.
4. Mood and Mental Health: Vitamin D may play a role in mood regulation and combating depression⁴.

Sources of Vitamin D

1. Sunlight: The skin synthesizes vitamin D upon exposure to UVB radiation. Factors such as geographic location, skin pigmentation, and sunscreen use can affect synthesis⁵.
2. Food: Few foods naturally contain vitamin D, but fatty fish, fish liver oils, and fortified foods can provide some amounts⁵.
3. Supplements: Vitamin D supplements are available in two forms: D2 (ergocalciferol) and D3 (cholecalciferol), with D3 being more effective at raising blood levels⁵.

Recommended Daily Allowances (RDA)

• Infants (0-12 months): 400 IU (10 mcg)
• Children (1-18 years): 600 IU (15 mcg)
• Adults (19-70 years): 600 IU (15 mcg)
• Adults over 70 years: 800 IU (20 mcg)
• Pregnant and breastfeeding women: 600 IU (15 mcg)⁶

Deficiency and Symptoms

• Children: Rickets, causing bone pain, poor growth, and skeletal deformities⁷.
• Adults: Osteomalacia, leading to bone pain and muscle weakness⁷.

Safety and Toxicity

• Safe Intake: Generally, doses up to 4,000 IU per day are considered safe for most people⁶.
• Toxicity: Excessive intake can lead to hypercalcemia (high levels of calcium in the blood), resulting in nausea, vomiting, weakness, and serious complications like kidney damage⁸. Vitamin D toxicity usually occurs due to high doses of supplements rather than from diet or sun exposure⁸.

Footnotes

1. Harvard T.H. Chan School of Public Health ↩ ↩²

2. MedlinePlus ↩

3. Mayo Clinic ↩

4. Psychiatry Research ↩

5. NIH Office of Dietary Supplements ↩ ↩² ↩³

6. NIH Office of Dietary Supplements ↩ ↩²

7. Harvard Health Publishing ↩ ↩²

8. Mayo Clinic ↩ ↩²