Home/Turner Syndrome
Condition Deep-Dive

Turner Syndrome (45,X)

A chromosomal condition in females characterized by the complete or partial absence of one X chromosome, affecting approximately 1 in 2,000 live female births1. Classic features include short stature, gonadal dysgenesis and a high lifetime risk of cardiovascular, renal5, thyroid and metabolic disease.

Hormonal & Women's Health Evidence-Based

Last updated:

โš ๏ธ Medication safety: please read first. The nutrition and supplement approaches on this page are meant to work alongside your prescribed treatment, never to replace it. Never stop, reduce or change your hormone treatment, including estrogen, without your prescriber's guidance. Doing so can be dangerous. Several supplements interact with hormone treatment, so talk to your prescriber or pharmacist before starting anything on this page.
Definition

What Is Turner Syndrome?

Turner syndrome is a chromosomal disorder in females in which one of the two X chromosomes is completely or partially missing. The result is a wide spectrum of physical features and a stack of medical risks, from short stature and ovarian failure to congenital heart defects, kidney anomalies, autoimmune thyroid disease and metabolic dysfunction.

Diagnosis is by karyotype, which identifies the specific chromosomal pattern. Classic Turner (45,X) accounts for about half of cases; the remainder are mosaic or structural X-chromosome variants, each with somewhat different risk profiles.

Turner syndrome is a lifelong condition. There is no "cure," but with comprehensive multidisciplinary care, including growth hormone4 in childhood, estrogen and progesterone replacement during adolescence and adulthood, cardiac and renal surveillance, and metabolic care, women with Turner syndrome can lead full, healthy lives.

A chart of chromosomes in pairs, 22 pairs and a single X chromosome boxed in red, labeled one X chromosome and 45,X

Classic Turner (45,X)

Complete absence of one X chromosome in all cells. The most common form.

  • โ†’Hallmarks: Short stature, primary amenorrhea, broad chest, neck webbing, lymphedema in infancy
  • โ†’Cardiac risk: Bicuspid aortic valve (over 25%), coarctation of the aorta (~10%), aortic dilation2

Mosaic Turner (45,X/46,XX or 45,X/46,XY)

Two or more cell lines, one 45,X and one with a normal or rearranged X (or Y) chromosome. Common1. Features tend to be milder and more variable.

  • โ†’Hallmarks: Milder phenotype; some women diagnosed only after infertility workup
  • โ†’Fertility: Spontaneous puberty and menarche more likely than with 45,X; overall only about one in five girls with Turner syndrome has spontaneous menarche, more often those with a mosaic karyotype8

Structural X Abnormalities

Includes isochromosome Xq (46,X,i(Xq)), ring X chromosome (46,X,r(X)) and X deletions. Less common. Phenotype depends on which X regions are affected, particularly the SHOX gene (short stature) and ovarian function genes on Xq.

  • โ†’Hallmarks: Variable short stature, gonadal dysgenesis and feature severity depending on loci involved

Mosaic with Y-Chromosome Material

About 10 to 12% of people with Turner syndrome have Y-chromosome material (45,X/46,XY, marker chromosomes containing Y). The concern is gonadoblastoma, a tumor of the undeveloped gonads, and whether and when to remove them is an individual decision made with the care team8.

  • โ†’Hallmarks: Female phenotype with Y-derived material; sometimes ambiguous external genitalia
  • โ†’Cancer risk: Reported gonadoblastoma rates vary widely between studies; the timing of any gonad removal is weighed against possible hormone function and fertility8
  • โ†’Fertility: Donor egg via gestational carrier may be considered; cardiac clearance essential
By the Numbers

Turner Syndrome by the Numbers

1 in 2,000
live female births worldwide8
Over 25%
have a bicuspid aortic valve, about 50 times the general rate, one reason heart imaging is standard at diagnosis8
164 per 100,000
person-years is the rate of aortic dissection, against 6 in the general population, so heart and aorta monitoring is lifelong8
61%
lifetime rate of autoimmune disease; Hashimoto's thyroiditis is the most common, so TSH is checked every 1 to 2 years8
18 to 60%
have a horseshoe kidney or another kidney or urinary tract anomaly, found on the renal ultrasound done at diagnosis8
36 to 84%
have hearing loss, so hearing is tested every 2 to 3 years in childhood and every 5 years in adults8
Signs & Symptoms

Symptoms of Turner Syndrome

Turner syndrome can present at any age, from prenatal ultrasound (nuchal edema, cardiac defects) through neonatal lymphedema, childhood short stature, adolescent absent puberty or adult infertility.

SymptomWhat happens
Growth, Skeletal & Reproductive Features
Short Stature (Final Height ~8 Inches Below Average)Untreated final adult height averages ~4'8" (143 cm), about 8 inches (20 cm) below average. Growth hormone, offered early in childhood, adds about 3 inches (7 cm) to adult height on average8.
Gonadal Dysgenesis & Primary AmenorrheaThe ovaries are typically "streak gonads" without functional follicles. Only about one in five girls has spontaneous periods, and natural conception is uncommon8. Estrogen induction is usually needed for breast development and uterine maturation.
Reduced Bone DensityA combination of low estrogen (until hormone replacement begins), a shorter skeleton and possible low vitamin D. Without adequate hormone replacement, fracture risk is substantially elevated by midlife.
Recurrent Otitis Media & Hearing LossAnatomic narrowing of the Eustachian tube leads to frequent childhood ear infections. Sensorineural hearing loss is common by adulthood; routine audiologic monitoring is part of standard care.
Lymphedema & Neck WebbingLymphedema of the hands and feet at birth, neck webbing (pterygium colli) from fetal nuchal cystic hygroma, and a low posterior hairline.
Cardiovascular, Renal & Metabolic Features
Bicuspid Aortic Valve & Aortic CoarctationThe most important monitoring priority in Turner is the aorta; regular echocardiograms and MRI imaging are part of lifelong care.
Aortic Dilation & Risk of DissectionSudden, severe pain in the chest, neck, shoulder, back or flank can be an aortic dissection and needs emergency care8. Aortic root dilation must be tracked over time and managed proactively with blood pressure control and exercise modifications.
Hypertension (Even in Childhood)Hypertension is common, often beginning in adolescence, sometimes earlier. Aggressive BP control is essential to protect the aorta.
Horseshoe Kidney & Collecting-System AnomaliesKidney and urinary tract differences are common, most often a horseshoe kidney or a duplicated collecting system8. Baseline renal ultrasound is standard at diagnosis.
Autoimmune Thyroid Disease & Celiac DiseaseHashimoto's thyroiditis is the most common autoimmune condition, and about 1 in 22 have celiac disease8.
Insulin Resistance & Metabolic SyndromeInsulin resistance, type 2 diabetes, central adiposity and dyslipidemia are all over-represented.
โš ๏ธ Pattern to watch for: A young girl who is short for her age, with recurrent ear infections and absent or delayed puberty, is the classic "second-look" Turner picture. Adults who were never diagnosed in childhood may present with infertility, hypertension or autoimmune disease; a karyotype confirms the diagnosis.
Causes

Causes of Turner Syndrome

Turner syndrome happens by chance and nothing a parent did causes it; each health risk that comes with it has a recommended check or treatment9.

CauseHow It Contributes to Turner SyndromeWhat Helps
A missing or partly missing X chromosomeThe cause of Turner syndrome itself; most of the time it happens by chance, and it is not linked to age or anything the parents did9. Diagnosis is by chromosome analysis of at least 30 cells8Diagnosis, genetic counseling and care from a team experienced in Turner syndrome; growth hormone may be offered from as young as 2 years if growth is falling behind8. Nothing in the diet changes the chromosomes
Ovaries that stop working earlyOnly about one in five girls has spontaneous periods, so most need hormone replacement at some point8; low estrogen is the main driver of weak bones6Estrogen replacement, usually from 11 to 12 years and continued to about 50 to 55 8; calcium and vitamin D from food, weight-bearing activity and bone scans, as the diet and diagnosis sections describe
Heart and aorta differencesA bicuspid aortic valve in over 25%, high blood pressure three to four times as often as in other women, and aortic dissection at young ages, on average 30 to 35 years8Lifelong heart and aorta imaging, a blood pressure check every year and treatment if it is high, regular aerobic activity and emergency care for sudden, severe chest, neck, shoulder, back or flank pain8
Autoimmune diseaseAutoimmunity affects 61% over a lifetime: Hashimoto's thyroiditis most often, then celiac disease in about 1 in 22 and low vitamin B12 8TSH every 1 to 2 years and celiac blood tests every 2 to 5 years from age 2; a gluten-free diet only once celiac disease is confirmed8
Kidney and ear structureKidney or urinary tract differences in 18 to 60%, and hearing loss, both conductive and sensorineural, in 36 to 84%8A kidney ultrasound at diagnosis and tests for any urinary symptoms; hearing tests every 2 to 3 years in childhood and every 5 years in adults, with hearing aids where needed8
Diabetes and metabolic riskDiabetes is common, with a lifetime rate of 25 to 70% in studies, and both type 1 and type 2 occur8HbA1c or fasting glucose every 1 to 2 years from age 10 to 12, exercise and the eating pattern in the diet section8
Diagnosis

How Turner Syndrome Is Diagnosed

Diagnosis is by karyotype, ideally with both peripheral blood and (when needed) a second tissue source to look for mosaicism. Workup at diagnosis and at regular intervals afterward covers cardiovascular, renal, endocrine, autoimmune and audiologic systems.

TestWhat it shows
At-Home / Pre-Diagnostic Observations
These observations build the case for formal karyotype testing, especially in girls whose features have been missed:
Growth-Chart TrackingPlot height on the pediatric growth chart at every visit. A girl whose height crosses two major percentile lines downward, falls below the 5th percentile or grows substantially below the parental midline target warrants endocrine and karyotype evaluation. Short stature is often the earliest sign.
Puberty & Cycle ObservationLack of breast development by age 13, absent menarche by age 15 or skipped/​stopped cycles after spontaneous menarche warrants FSH, LH, AMH and karyotype.
Lab & Clinical Tests
Karyotype (Diagnostic Standard)Peripheral-blood karyotype of at least 30 cells is the gold standard. If mosaicism is suspected and the initial study is normal but suspicion remains high, a second tissue (skin fibroblast or buccal mucosa) may be analyzed. Identifies the specific Turner variant.
Reproductive Hormone PanelFSH and LH are typically elevated; estradiol low; AMH very low or undetectable in classic Turner; may be measurable in mosaic Turner. These confirm gonadal dysgenesis and guide HRT planning.
Echocardiogram & Cardiac MRIEchocardiogram at diagnosis for all patients; cardiac MRI by adolescence for high-resolution imaging of the aorta. Repeat imaging based on findings, typically every 5 to 10 years if normal, more often if dilation or other abnormalities.
Renal UltrasoundBaseline ultrasound at diagnosis. UTI history should trigger repeat imaging or referral.
Regular Thyroid & Celiac ScreeningTSH, with or without free T4, every 1 to 2 years starting at age 2; tissue transglutaminase IgA with total IgA from age 2, then every 2 to 5 years. Address Hashimoto's and celiac early to prevent fatigue, growth issues and bone loss.
Metabolic & Bone Density WorkupHbA1c or fasting glucose every 1 to 2 years from age 10 to 12, and lipids every 3 years. DXA scan after growth ends and before 21, then every 5 to 10 years; sooner if HRT adherence has been imperfect8. 25-⁠OH-D, calcium, ferritin, B12 as part of nutrient panel.
Treatment Comparison

Conventional and Holistic Treatment for Turner Syndrome

Turner syndrome is a lifelong chromosomal condition. The conventional pillars (growth hormone in childhood, estrogen-progesterone replacement from adolescence to about age 50 to 55, and surveillance imaging) are essential and not replaceable by holistic care. Holistic strategies layer on top to support cardiovascular health, bone, gut, autoimmune balance and quality of life.

๐ŸŒฟ HOLISTIC
๐Ÿ’Š CONVENTIONAL
๐ŸŒฟ

Holistic / Functional Approach

Layered on standard medical care; supports cardiovascular, bone, gut, autoimmune and psychological well-being

Primary Focus
Cardiovascular protection, bone support, autoimmune mitigation, mental health care, fertility counseling
Duration
Lifelong; integrated with conventional medical care
Effect on Underlying Disorder
Does not change karyotype; reduces secondary risks & supports daily living
Fertility Outcome
Donor-egg IVF is the standard fertility pathway and requires aortic clearance; rare spontaneous pregnancy in mosaic Turner

Full Holistic Approach Includes

  • Heart-healthy, Mediterranean-style eating with adequate protein, omega-⁠3 and polyphenols for aortic and metabolic protection
  • Bone-supportive nutrition (adult amounts; for a child or teenager, her pediatric endocrinologist sets them), calcium 1,000 to 1,200 mg/day, vitamin D 1,000 to 3,000 IU/day, magnesium, K2, protein. The upper intake level for supplemental magnesium is 350 mg/day; above that, diarrhea is common. With kidney disease, take it only on your clinician's advice.
  • Strength training and weight-bearing exercise (cleared with cardiology for safety) for bone and metabolic health
  • Celiac screening before any change to gluten, since removing gluten first makes the test unreliable; a strict gluten-free diet only once celiac disease is confirmed
  • Blood pressure management, low-sodium, potassium-rich foods, weight management, stress reduction
  • Mental health support, peer community (Turner Syndrome Society, Turner Syndrome Foundation), therapy for body-image and fertility grief
  • Coordinated multidisciplinary follow-up: endocrinology, cardiology, gynecology, audiology and mental health
โš ๏ธ Important boundaries: Holistic care is complementary and does not replace HRT, growth hormone or surveillance imaging. Any pregnancy attempt in a woman with Turner syndrome requires cardiac clearance because aortic dissection risk is markedly increased; spontaneous and donor-egg pregnancies must be cardiology-cleared and managed in a high-risk maternal-fetal medicine setting.
Supplement Protocol

Evidence-Based Supplements for Turner Syndrome

Supplements complement HRT and growth hormone (when used), supporting bone, cardiovascular health, autoimmune balance, mood and energy. All should be coordinated with your endocrinologist and cardiologist. The amounts below are for adults. For a child or teenager, her pediatric endocrinologist sets every supplement and dose, because several of these amounts are above the upper limits for children11.

Supplement What it is for Typical range Timing Notes & cautions
Vitamin D3 (with K2)Foundational for bone, and involved in immune regulation. Critical given high baseline osteoporosis and autoimmune thyroid risk.1,000 to 3,000 IU D3 + 100 to 200 mcg MK-⁠7 K2 per dayWith a fat-containing mealTest 25-⁠OH-D. Severe deficiency is corrected under clinical supervision. The adult tolerable upper intake level is 4,000 IU/day; higher intakes need a blood test and a clinician. If you take warfarin, clear any vitamin K supplement with the clinician managing your anticoagulation before starting or stopping it: vitamin K antagonizes warfarin, and changing your intake destabilizes the INR. Consistency matters more than avoidance. This does not apply in the same way to direct oral anticoagulants such as apixaban or rivaroxaban, but tell your prescriber about any supplement you take.
CalciumBone-mineralization foundation, especially in adolescence and adulthood. It is often paired with K2, though supplement benefits of K2 for bone and arteries are not established.500 to 1,000 mg/day supplement, to reach 1,000 to 1,200 mg/day from food and supplement combinedSplit doses, with mealsFood-first; supplement only if dietary calcium below 1,000 mg/day. Avoid more than 500 mg per dose.
Magnesium GlycinateSupports bone, blood pressure, insulin sensitivity, sleep and mood. Often low across the population.200 to 400 mg elemental magnesium per dayEvening, 30 to 60 min before bedThe top of this range is above the 350 mg/day upper intake level for supplemental magnesium; above that, diarrhea is common. With kidney disease, take it only on your clinician's advice.
Omega-⁠3 EPA/DHANot shown to protect the aorta or heart in Turner syndrome; fatty fish is the preferred source.2 to 3 g combined EPA+DHA per dayWith mealsChoose a product with independent third-party purity testing. Pause about 1 week before any planned surgery. Pregnant or planning a pregnancy: check the dose with your doctor. In heart trials, fish oil supplements raised the risk of atrial fibrillation, an irregular heartbeat, more so above 1 g a day12, so check this dose with your clinician first.
B-ComplexSupports methylation, neurotransmitter balance, energy and homocysteine metabolism (cardiovascular risk marker).1 capsule per day per product labelMorning with foodStandard or methylated forms both work for most people.
SeleniumRequired for thyroid function and glutathione peroxidase. Studied in Hashimoto's thyroiditis with mixed results.100 to 200 mcg per dayWith foodTwo Brazil nuts per day is a food alternative; do not exceed 400 mcg/day.
Iron (if needed)For iron-deficiency anemia, common in adolescent and adult women, particularly if menstruating on cyclic HRT.20 to 65 mg elemental iron, only if ferritin lowEmpty stomach with vitamin CBisglycinate avoids GI side effects. Confirm ferritin less than 50 ng/mL before supplementing. The top of this range sits above the 45 mg/day tolerable upper intake level for adults. That is appropriate only when correcting a confirmed deficiency under clinical supervision, not as general supplementation. Test ferritin first, and retest rather than staying on it indefinitely. In pregnancy or when planning one, your midwife or doctor sets the dose.
Vitamin B12Supports red-blood-cell formation, energy and neurologic function. Frequently low in autoimmune contexts.500 to 1,000 mcg per day sublingualMorningSublingual or injectable forms bypass gut absorption issues.
ZincRequired for immune function, growth, taste/​smell and bone metabolism. Often modestly low in restrictive eaters.10 to 25 mg per dayWith mealsAdd 1 to 2 mg copper if using more than 8 weeks at higher doses.
What to Expect

What to Expect Over Time

Care is lifelong, and the international guideline sets what is checked and when.

Treatment and supportive care, together
First Weeks

At diagnosis: a heart ultrasound, a kidney ultrasound, a hearing check and referral to a team experienced in Turner syndrome, with genetic counseling for the family8.

Months 1 to 3

In childhood, growth hormone may be offered if growth is falling behind; on average it adds about 3 inches (7 cm) to adult height8. Adolescents and adults newly diagnosed have heart MRI within 12 months, and blood pressure is checked every year8. The diet in this guide supports bone and heart health alongside this care.

Months 3 to 12

For girls whose ovaries are not working, low-dose estrogen usually starts at 11 to 12 and rises slowly over 2 to 4 years, with progesterone added once bleeding starts8. TSH every 1 to 2 years and celiac tests every 2 to 5 years run from age 2.

Long Term

Estrogen usually continues to about 50 to 55. Heart imaging continues for life, at least every 5 to 10 years in adults; hearing every 5 years; bone scans every 5 to 10 years8. Pregnancy carries higher risks and needs heart imaging within 2 years before trying3.

When to Seek Care

Call 911 or go to the emergency department for sudden, severe pain in the chest, neck, shoulder, back or flank: it can be an aortic dissection10. See your team promptly for any new chest pain, urinary symptoms or a change in hearing8.

📬

Get new guides in your inbox. Once a month: new condition guides and research updates, including the trials that did not work. Free, no spam, and you can unsubscribe in one click.

Sign up

Next Steps

Lifelong Surveillance Protects the Heart

Care is lifelong, with heart imaging for life and estrogen replacement that protects bone and cardiovascular health. The diet in this guide supports bone and heart health alongside this care. Sudden severe pain in the chest, neck, shoulder, back or flank means calling 911 or going to the emergency department.

Explore Primary Ovarian Insufficiency (POI) โ†’ Explore High Blood Pressure โ†’

References & Evidence Notes

Each numbered entry below is either a source you can follow or a note setting out what the evidence does and does not support. Both are numbered together so the markers in the text line up.

Last reviewed October 20, 2026. Supplement entries are cross-checked against the NIH National Center for Complementary and Integrative Health and the Linus Pauling Institute Micronutrient Information Center.7 One item on this page outranks everything else in the nutrition sections. Aortic dissection is the leading cause of premature death in Turner syndrome, and it is largely preventable with surveillance. Bicuspid aortic valve, coarctation and aortic dilation are common, lifelong cardiac imaging is standard care rather than optional, and pregnancy substantially raises dissection risk and requires specialist pre-pregnancy cardiac assessment. Sudden, severe pain in the chest, neck, shoulder, back, flank or abdomen in someone with Turner syndrome is an emergency until proven otherwise. Alongside that, estrogen replacement from adolescence until the usual age of menopause protects bone and cardiovascular health, and under-replacement is a common and consequential failure. Nutrition supports all of this; it substitutes for none of it.

  1. On the condition: Turner syndrome results from complete or partial absence of one X chromosome, affecting roughly 1 in 2,000 to 2,500 live female births, with mosaicism common. Presentation ranges from prenatal detection to diagnosis in adulthood during investigation of short stature or primary amenorrhea. Late diagnosis is frequent and means missed surveillance. ↩
  2. On cardiovascular surveillance. Bicuspid aortic valve occurs in roughly a third and coarctation of the aorta in around 10%, PubMed 40822698. Aortic dilation and dissection risk is increased, and dissection occurs at younger ages and smaller aortic diameters than in the general population, which is why Turner-specific indexed measurements are used. Guidelines recommend baseline and periodic cardiac imaging by echocardiography and MRI across the lifespan, with frequency set by findings and risk factors including hypertension. ↩
  3. On pregnancy: pregnancy, whether spontaneous or by oocyte donation, carries a markedly increased risk of aortic dissection; Turner syndrome is among the heritable conditions predisposing to aortic disease that reviews of aortopathy in pregnancy single out for early detection and planning, PubMed 41369177, and pre-pregnancy cardiac assessment with specialist counseling is essential. Blood pressure control matters throughout. This is one of the few situations where a cardiology opinion should precede a fertility decision. ↩
  4. On growth hormone and estrogen: growth hormone increases adult height and is standard in childhood. Estrogen replacement is generally begun around the usual age of puberty and continued to the average age of menopause, with progestin added once bleeding is established. Adequate replacement protects bone density and cardiovascular health, and premature discontinuation is a recognized problem in the transition from pediatric to adult care. ↩
  5. On the rest of the surveillance schedule, because it is easy to lose in adulthood: renal anomalies affect a substantial minority and warrant baseline imaging; autoimmune thyroid disease and celiac disease are markedly more common and are screened for periodically; hearing loss is progressive and needs audiology; and metabolic risk including type 2 diabetes and dyslipidemia is raised. This is where nutrition genuinely contributes. ↩
  6. On bone: fracture risk is increased, driven principally by estrogen deficiency, with vitamin D insufficiency and celiac disease as contributors. Calcium and vitamin D adequacy and weight-bearing exercise matter, alongside rather than instead of hormone replacement. ↩
  7. National Center for Complementary and Integrative Health (NIH), nccih.nih.gov, and the Linus Pauling Institute Micronutrient Information Center, lpi.oregonstate.edu/mic. ↩
  8. On Turner syndrome care: the 2024 international guideline reports that about one in five girls with Turner syndrome has spontaneous menarche, more often with a mosaic karyotype; recommends TSH every 1 to 2 years and celiac screening every 2 to 5 years from age 2; reports kidney and urinary tract anomalies in 18 to 60%; gives an aortic dissection incidence of about 164 per 100,000 person-years against 6 in the general population and advises prompt care for sudden, severe chest, neck, shoulder, back or flank pain; recommends heart imaging for life, a kidney ultrasound at diagnosis and hearing tests every 2 to 3 years in childhood and every 5 years in adults; reports a mean adult height gain of about 7 cm with growth hormone; recommends low-dose estrogen from 11 to 12 years when needed, continued to about 50 to 55; reports Y-chromosome material in 10% to 12%; and recommends an individual decision about removing the gonads, since reported gonadoblastoma rates vary widely, PubMed 38748847. ↩
  9. On what causes Turner syndrome: NHS guidance explains that it is caused by a missing or partly missing sex chromosome, that it very rarely passes from a parent and most of the time happens by chance, that it is not linked to age or anything the parents did before or during pregnancy, and that most people with Turner syndrome should be able to live a relatively normal, healthy life with regular health checks and early treatment, NHS, Turner syndrome. ↩
  10. On aortic dissection: MedlinePlus explains that symptoms usually begin suddenly with severe chest pain, often sharp, tearing or ripping, felt below the breastbone and moving under the shoulder blades or to the back, and that it can spread to the shoulder, neck, arm, jaw, abdomen or hips; anyone with these symptoms or severe chest pain should call emergency services or go to the emergency room as quickly as possible, MedlinePlus, aortic dissection. ↩
  11. On upper limits for children: the NIH Office of Dietary Supplements gives tolerable upper intake levels for supplemental magnesium of 65 mg a day at ages 1 to 3 and 110 mg at ages 4 to 8, NIH Office of Dietary Supplements, magnesium; for zinc of 7 mg at ages 1 to 3, 12 mg at ages 4 to 8 and 23 mg at ages 9 to 13, zinc; for iron of 40 mg a day up to age 13, iron; and for vitamin D of 2,500 IU a day at ages 1 to 3 and 3,000 IU at ages 4 to 8, vitamin D. ↩
  12. Gencer B, Djousse L, Al-Ramady OT, Cook NR, Manson JE, Albert CM. Effect of long-term marine omega-⁠3 fatty acids supplementation on the risk of atrial fibrillation in randomized controlled trials of cardiovascular outcomes: a systematic review and meta-analysis. Circulation. 2021;144(25):1981-⁠1990. PubMed 34612056. Seven trials with 81,210 people followed for about 5 years: omega-⁠3 supplements were linked to a higher risk of atrial fibrillation (hazard ratio 1.25), more so in trials of more than 1 g a day (1.49), and the risk rose with each additional gram. ↩