When it comes to you managing your health, an early warning system is a distinct advantage. That’s where blood tests come in: They're an important tool for assessing your overall health, and provide valuable insight into any potential issues that may be developing.
Your health care provider likely orders a standard screening panel at your annual physical. The problem is, these tests may not pick up on some important nutritional deficits that can impact your health.
Why Do I Need Special Blood Tests?When following a diet of high-nutrient plant foods, it's important to ensure that you're getting optimal amounts of some vitamins, minerals, and fatty acids that are more available in animal products.
How Often Do I Need These Tests?The recommended schedule would be to have these tests every five years for adults younger than 65, and every three years for those aged 65 and older.
Vitamin B12 and Methylmalonic AcidVitamin B12 isn't naturally present in plant foods, and insufficiency is common, especially in those older than age 60, because B12 absorption becomes less efficient as we age.
Having results for both B12 and MMA is helpful, as a high MMA might indicate a mild deficiency or a developing deficiency if B12 results are on the lower end of the normal range.
HomocysteineVitamin B12 acts as a coenzyme for methionine synthase, which produces methionine from homocysteine. Deficiency in B12 (or folate) results in the accumulation of homocysteine.2
FerritinFerritin is a protein that stores iron. A low ferritin level in the blood indicates iron deficiency. The iron in plant foods is less absorbable than that from animal foods, and some people on a vegan or near-vegan diet, especially women who are pregnant or of childbearing age, may require iron supplementation. Having too much iron can also create health problems.
Favorable ranges Men: 50–336 µg/L Women: 40–307 µg/L
Hemoglobin A1CHemoglobin A1c (HbA1C) is an indicator of long-term (about three months) blood glucose levels. The test measures the percentage of hemoglobin in the blood that is glycosylated (attached to a sugar molecule). More glycosylated hemoglobin is formed at higher blood glucose concentration, and it accumulates over the lifetime of the cell.6 A high HbA1c level indicates prediabetes or diabetes.
Vitamin DThe primary source of vitamin D is sunlight, and supplementation is appropriate to ensure year-round vitamin D adequacy and prevent skin damage from excessive sun exposure. Low vitamin D levels are associated with osteoporosis, depression, autoimmune disease, cancer, and diabetes.7 Excessively high vitamin D levels may also be harmful to health.8–12
Omega-3 IndexThe long-chain omega-3 fatty acids DHA and EPA are usually supplied by fatty fish. DHA and EPA are important structural and functional components of brain and retinal cell membranes, and have anti-inflammatory and cardiovascular benefits.13
Insulin-Like Growth Factor 1This test is for those 75 years old and older. Insulin-like growth factor 1 (IGF-1) is a growth-promoting hormone important during childhood and adolescence. IGF-1 levels peak during our teens and 20s and then decline as we age. In adults, circulating IGF-1 is primarily determined by protein intake; animal protein increases IGF-1 more than plant protein, and dairy protein is the strongest IGF-1 elevator.20,21 A high IGF-1 level is linked to accelerated aging and an increased risk of cancer and premature death.22–26
Oxidized LDL or Measured LDL CholesterolThis test is for those with a history of LDL cholesterol higher than 110 mg/dl.
Elevated low-density lipoprotein (LDL) cholesterol is one of many risk factors for cardiovascular disease. However, oxidized LDL (oxLDL) is a more important marker of disease risk than total LDL, because oxidized LDL is more atherogenic (plaque formation-promoting) than native LDL.
- Office of Dietary Supplements, National Institutes of Health. Dietary Supplement Fact Sheet: Vitamin B12 [http://ods.od.nih.gov/factsheets/VitaminB12/]
- Hannibal L, Lysne V, Bjorke-Monsen AL, et al. Biomarkers and Algorithms for the Diagnosis of Vitamin B12 Deficiency. Front Mol Biosci 2016, 3:27.
- Ganji V, Kafai MR. Population Reference Values for Serum Methylmalonic Acid Concentrations and Its Relationship with Age, Sex, Race-Ethnicity, Supplement Use, Kidney Function and Serum Vitamin B12 in the Post-Folic Acid Fortification Period. Nutrients 2018, 10.
- Mineva EM, Sternberg MR, Zhang M, et al. Age-specific reference ranges are needed to interpret serum methylmalonic acid concentrations in the US population. Am J Clin Nutr 2019, 110:158–168.
- Moretti R, Caruso P. The Controversial Role of Homocysteine in Neurology: From Labs to Clinical Practice. Int J Mol Sci 2019, 20.
- Fayyaz B, Rehman HJ, Minn H. Interpretation of hemoglobin A1C in primary care setting. J Community Hosp Intern Med Perspect 2019, 9:18–21.
- Holick MF. Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. American Journal of Clinical Nutrition 2004, 80:1678S–1688S.
- Durup D, Jorgensen HL, Christensen J, et al. A reverse J-shaped association of all-cause mortality with serum 25-hydroxyvitamin D in general practice: the CopD study. J Clin Endocrinol Metab 2012, 97:2644–2652.
- Durup D, Jorgensen HL, Christensen J, et al. A reverse J-shaped association between serum 25-hydroxyvitamin D and cardiovascular disease mortality - the CopD-study. J Clin Endocrinol Metab 2015:jc20144551.
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- Zittermann A, Iodice S, Pilz S, et al. Vitamin D deficiency and mortality risk in the general population: a meta-analysis of prospective cohort studies. Am J Clin Nutr 2012, 95:91–100.
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- Harris WS, Tintle NL, Imamura F, et al. Blood n-3 fatty acid levels and total and cause-specific mortality from 17 prospective studies. Nature Communications 2021, 12:2329.
- Coley N, Raman R, Donohue MC, et al. Defining the Optimal Target Population for Trials of Polyunsaturated Fatty Acid Supplementation Using the Erythrocyte Omega-3 Index: A Step Towards Personalized Prevention of Cognitive Decline? J Nutr Health Aging 2018, 22:982–998.
- Lukaschek K, von Schacky C, Kruse J, Ladwig KH. Cognitive Impairment Is Associated with a Low Omega-3 Index in the Elderly: Results from the KORA-Age Study. Dement Geriatr Cogn Disord 2016, 42:236–245.
- Craddock JC, Probst YC, Neale EP, Peoples GE. A Cross-Sectional Comparison of the Whole Blood Fatty Acid Profile and Omega-3 Index of Male Vegan and Omnivorous Endurance Athletes. J Am Coll Nutr 2021:1–9.
- Sarter B, Kelsey KS, Schwartz TA, Harris WS. Blood docosahexaenoic acid and eicosapentaenoic acid in vegans: Associations with age and gender and effects of an algal-derived omega-3 fatty acid supplement. Clin Nutr 2014.
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- Doi T, Shimada H, Makizako H, et al. Association of insulin-like growth factor-1 with mild cognitive impairment and slow gait speed. Neurobiol Aging 2015, 36:942–947.
- Calvo D, Gunstad J, Miller LA, et al. Higher serum insulin-like growth factor-1 is associated with better cognitive performance in persons with mild cognitive impairment. Psychogeriatrics 2013, 13:170–174.
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