Introduction

Purpose of the guide

The Supplements 101 guide is designed to provide comprehensive, evidence-based information on supplements for health optimization. This guide aims to help understand the role of supplements and how they can bridge nutritional gaps and support overall health. Exploring the complex world of dietary supplements will show how these products can help maintain optimal health when used as part of a personalized approach to nutrition and wellness.

Overview of supplements and their role in health

Supplements are products designed to augment the daily intake of nutrients, including vitamins, minerals, and other beneficial compounds. They have become increasingly important due to several factors in modern life that can lead to nutritional deficiencies or increased nutrient needs.

It is necessary to recognize that dietary supplements are not inert substances; they can have potent biological effects that must be taken seriously. The common misconception that "more is better" when it comes to supplements can lead to harmful consequences, as excessive intake of certain nutrients can cause toxicity and damage to the body. Supplements should be taken with the same level of caution as medications, as proper dosing is key to avoiding adverse effects.¹

Despite some studies suggesting that supplements are unnecessary,² these findings are often limited by a narrow scope and fail to consider the broader nutritional landscape.³ Often, they focus narrowly on specific populations or nutrients, failing to account for the complex realities of human nutrition. Moreover, many Americans do not consume nutrient-dense foods due to the convenience of processed options,⁴ financial constraints, and a general lack of nutritional knowledge.⁵ Objective laboratory tests frequently reveal nutrient deficiencies, indicating that diet alone may not provide all the necessary nutrients. Therefore, supplementation can play an important role in filling these gaps and supporting overall health.

Lifestyle factors also play a key role in the need for supplementation.⁶ Many people do not adhere to the recommendations described by the USDA Dietary Guidelines for Americans for a healthy diet. Instead, a significant portion of the population follows what is known as the Standard American Diet (SAD). This dietary approach is characterized by a high intake of processed foods, refined sugars, and unhealthy fats, coupled with a low intake of fruits, vegetables, and whole grains.⁷ Such a diet can lead to numerous nutritional deficiencies and increase the risk of chronic diseases.

Even for those who strive to eat a healthy diet, the way food is prepared can impact its nutritional value. The act of cooking can change the nutrient content of consumed food, depending on the cooking method used.⁸ For example, some cooking methods can reduce the content of water-soluble vitamins in vegetables, while others might increase the bioavailability of certain nutrients.

Another significant factor is the reduced nutrient density in food due to soil depletion. Modern agricultural practices have led to a decrease in the nutrient content of fruits and vegetables.⁹ This means that even individuals who consume a diet rich in fruits and vegetables may not be getting the same level of nutrients that previous generations did from the same foods.

By filling these nutritional gaps, supplements can play an essential role in supporting specific health conditions and enhancing overall well-being. They can provide nutrients that might be lacking in the diet, help meet increased nutrient needs due to various factors, and potentially reduce the risk of certain health problems.

Root Cause Approach to Supplements

Supplements play an important role in addressing the root causes of various conditions by supporting the body’s biochemical processes and correcting nutritional deficiencies that may contribute to disease development.¹⁰ Unlike conventional approaches that often focus on symptom management, a root cause approach uses supplements as a tool in addition to strategies that help identify and address underlying imbalances. For example, magnesium deficiency has been linked to cardiovascular issues and metabolic syndrome.¹¹ Supplementing with magnesium can help mitigate these issues and support the body’s natural healing processes.

Additionally, supplements can enhance the efficacy of a comprehensive treatment plan by providing targeted support to specific systems or functions. For instance, chromium deficiencies are linked with insulin resistance.¹² Besides addressing diet and lifestyle factors associated with insulin resistance, supplementing with chromium addresses the root cause. With this approach, supplements are used not in isolation but as part of a broader strategy that includes lifestyle modifications, dietary changes, and other personalized interventions to restore balance and promote optimal health. This enables a more nuanced understanding of disease management and fosters more comprehensive, individualized care.

Importance of evidence-based supplement use

In the vast and often confusing world of dietary supplements, it is important to rely on scientifically validated information when making decisions about supplement use. This guide emphasizes the importance of an evidence-based approach to supplementation, which means using supplements based on solid scientific research and individual health needs.

The prudent use of supplements can be beneficial for both longevity and health span–the period of life when a person is healthy and free from serious or chronic disease.¹³ This is accomplished by taking a personalized approach to supplementation that ensures you get the specific nutrients you need for maintaining optimal health.

However, supplements are not a magic solution or a replacement for a healthy lifestyle. They should be used in conjunction with a nutrient-rich diet (see Nutrition 101), regular exercise (see Exercise 101), stress management (see Mental Health 101 and Stress Management 101), optimizing gut health (see Gut Health 101), and adequate sleep (see Sleep 101). The goal is to use supplements as part of a comprehensive approach to health, not as a quick fix or a substitute for healthy habits.

Evidence-based supplement use involves several key principles:¹⁴

• Choosing supplements that have been proven effective in well-designed scientific studies;
• Understanding potential interactions with medications or other supplements;
• Using the correct dosage based on research and individual needs;
• Recognizing when a supplement might be beneficial and when it might not be necessary;
• Regularly reassessing supplement needs based on changes in health status, diet, or lifestyle; and
• Understanding the risk. Supplements can have powerful effects on the body and must be taken seriously.

Following these principles can maximize the potential benefits of supplements while minimizing risks.

Nutritional support and rationale for supplements

While a balanced diet should be the primary source of nutrients, supplements can play an essential role in supporting overall health for several reasons:

• Dietary restrictions: Vegetarian, vegan, or other restricted diets may lead to deficiencies in certain nutrients.¹⁵ For example, vegetarians and vegans may need to supplement with vitamin B12, which is primarily found in animal products. Similarly, individuals following a dairy-free diet might need calcium and vitamin D supplements. ddf
• Digestive issues: Some individuals may have difficulties absorbing nutrients due to digestive disorders or age-related changes.¹⁶ Conditions such as inflammatory bowel disease, celiac disease, or simply the natural aging process can impair nutrient absorption, making supplementation necessary to meet nutritional needs.
• Increased nutrient needs: Various factors can increase an individual's nutrient requirements. These include stress, environmental toxins (see Environmental Health 101), and certain health conditions.¹⁷ For example, chronic stress can deplete certain vitamins and minerals, while exposure to environmental pollutants may increase the need for antioxidants.
• Medication-induced nutrient depletion: Some medications can interfere with nutrient absorption or increase nutrient needs. For example, long-term use of proton pump inhibitors can lead to vitamin B12 deficiency, while certain diuretics can deplete potassium and magnesium.¹⁸
• Nutrient depletion in soil: Modern agricultural practices have led to soil depletion, resulting in lower nutrient content in fruits and vegetables.⁹ This means that even a diet rich in these foods may not provide optimal levels of all nutrients.
• Specific health conditions: Certain health conditions or life stages may increase the need for specific nutrients.¹⁹ Pregnancy, for instance, increases the need for folate, iron, and other nutrients.²⁰ Chronic diseases may also alter nutrient needs or impair nutrient absorption.

Given these factors, certain foundational supplements often benefit many individuals. These include:

• Magnesium: This mineral is involved in over 300 enzymatic reactions in the body, including energy production, muscle function, and nervous system regulation. Despite its importance, many people don't get enough magnesium through their diet.²¹
• Multivitamin: A high-quality multivitamin can help fill general nutritional gaps and provide a broad spectrum of essential nutrients. It serves as a nutritional insurance policy, helping to ensure that the body receives adequate amounts of vitamins and minerals even when the diet is less than perfect.²²
• Omega-3 fatty acids: These essential fats, primarily found in fatty fish, are crucial for heart and brain health. They have anti-inflammatory properties and support cognitive function. Many people don't consume enough omega-3s through diet alone, making supplementation beneficial.²³
• Probiotics: These beneficial bacteria support gut health and immune function. While fermented foods can provide probiotics, supplementation can be helpful, especially after antibiotic use or for those with digestive issues.²⁴
• Vitamin D3 with K2: Vitamin D is essential for bone health, immune function, and numerous other bodily processes. Many people are deficient in vitamin D, especially those living in northern latitudes or who spend little time outdoors. Vitamin K2 works synergistically with vitamin D to support bone and cardiovascular health.²⁵

The subsequent sections of this guide will provide more detailed information on these and other supplements, including their benefits, proper use, and potential risks. It will also discuss how to choose high-quality supplements and how to integrate them into a healthy lifestyle for optimal benefits.

Function Health's Approach to Supplements

Personalized Medicine

The approach to supplementation should be tailored to each individual's unique needs, taking into account various factors that can influence nutrient requirements and absorption.²⁶

Epidemiology of nutrient deficiencies

Nutrient deficiencies are surprisingly common, even in developed countries.

• Magnesium: An estimated 48% of Americans consume less than the required amount of magnesium.²⁷
• Iron: Iron deficiency anemia affects more than 30% of the world's population, with higher rates in women and children.²⁸ Furthermore, iron deficiency without anemia or low iron stores is estimated to be at least twice as common.²⁹
• Vitamin B12: This deficiency affects up to 20% of older adults and is common in vegetarians and vegans.³⁰
• Vitamin D: Up to 41.6% of adults in the United States are vitamin D-deficient.³¹

Individual health assessments and the importance of testing

Comprehensive health assessments and testing are crucial to determine an individual's specific supplement needs.³² These may include:

• Blood tests to check levels of vitamins, minerals, and other biomarkers;³³
• Genetic testing to identify potential predispositions to certain nutrient deficiencies;³⁴
• Gut health assessments to evaluate nutrient absorption capabilities;³⁵ and
• Lifestyle and dietary assessments to identify potential nutrient gaps.³⁶

Genetic predispositions

Genetic factors can significantly influence an individual's nutrient needs and how their body processes certain supplements. In fact, one of our DNA codes for enzymes, and each of those enzymes requires a cofactor. These cofactors are vitamins, minerals, and phytonutrients. Variations in these genes are common. Those variations in enzyme function often necessitate different forms or doses of nutrients to function optimally. For example:

• MTHFR gene mutations can affect folate metabolism, potentially increasing the need for methylated forms of B vitamins.³⁷
• Variations in the VDR gene: can impact vitamin D absorption and metabolism, potentially necessitating higher vitamin D intake.³⁸

Lifestyle factors

Various lifestyle factors can influence supplement needs.

• Chronic stress: May deplete B vitamins,³⁹ vitamin C,⁴⁰ and magnesium.⁴¹ It can also negatively affect gut health.⁴²
• High levels of physical activity: Can increase the need for certain nutrients like magnesium and antioxidants.⁴³
• Vegetarian or vegan diets: May require supplementation of vitamin B12, iron, zinc, and omega-3 fatty acids.¹⁵

Function Tests to Assess Health Status and Need for Supplementation

To effectively determine the need for supplementation, it is important to get a comprehensive evaluation of the functioning of all body systems. A Function membership includes a variety of tests that can support this process towards choosing the most optimal supplement for health. This comprehensive testing can provide insight into the status of the cardiovascular system, immune regulation, kidney function, liver function, metabolic processes, and nutrient levels, as well as monitor electrolytes and gut health and more. Understanding how these systems function can help inform the decision-making process when choosing which supplements may best support overall health or health conditions. Below are some of the core Function tests to get started:

Blood: Blood tests provide a comprehensive overview of overall health by measuring various blood components, such as red and white blood cells and platelets, to detect anemia, infections, and other underlying medical conditions.

• Purpose: Detects conditions like anemia, infection, and other diseases.⁴⁴
• Supplement needs: Identifies the need for zinc, iron, vitamin B12, and folate supplementation that may contribute to anemia and infections.

Metabolic: These tests provide a broad overview of metabolic health by evaluating glucose levels, electrolyte balance, and kidney and liver function, helping to identify potential issues such as diabetes, kidney disease, or liver dysfunction.

• Purpose: Evaluates kidney and liver function, electrolyte balance, and blood glucose levels.⁴⁵
• Supplement needs: Identifies imbalances that might necessitate supplementation with electrolytes, protein, or liver support supplements.

Food sensitivity test: A food sensitivity test helps identify specific foods that may trigger adverse reactions, enabling an individual to make informed dietary choices and alleviate symptoms such as digestive issues, fatigue, or inflammation.

• Purpose: Detects immune responses to specific foods that may contribute to inflammation and other health issues.⁴⁶
• Supplement needs: Helps identify needs for gut-healing supplements and anti-inflammatory nutrients.

Heavy metals: The heavy metals panel can be used to determine if exposure to these toxins is contributing to an individual's health concerns.

• Purpose: Detects toxic metal exposure such as lead, mercury, and aluminum.⁴⁷
• Supplement need: Identifies the need to supplement with chelation agents, methylation support, detoxification minerals (Zn, Se), glutathione-supporting nutrients (ALA, NAC), antioxidants, and minerals (e.g., zinc, magnesium).

Hormones: Provides critical insights into hormonal imbalances, helping diagnose and manage conditions related to mood, energy levels, reproductive health, overall endocrine function, and more.

• Purpose: Measures various hormone levels (e.g., cortisol, thyroid hormones, and sex hormones).
• Supplement needs: Identifies imbalances that may require hormone-supporting supplements like adaptogens, thyroid support supplements, or bioidentical hormones.

Micronutrient testing: A Function membership includes 20 core lab tests to assess overall nutrient status and determine what specific micronutrient deficiencies might be present. Some of these core tests include magnesium, omega-3 and 6 fatty acids, vitamin D, and iron. In addition to testing the micronutrient levels, additional tests are included that can determine the potential root causes of these deficiencies:

• Essential fatty acids (EFA) testing: Assesses the balance of omega-3 and omega-6 fatty acids to guide dietary and supplementation recommendations.⁴⁸‍
  • Supplement needs: Identifies the need to supplement with omega-3 fatty acids (EPA/DHA).

• Magnesium test: Magnesium is a mineral imperative for cells to make energy, for chemical pumps to work and stabilize membranes, and to help muscles relax. Low magnesium can impact calcium, potassium, phosphorus, and/or parathyroid hormone. This test helps evaluate absorption and helps determine whether or not there is a problem with kidney function or the gastrointestinal tract.‍
  • Supplement needs: Identifies the need for dietary assessment and supplementation with magnesium.

• Vitamin B testing: When testing for B vitamins, two core lab tests are included, such as homocysteine and methylmalonic acid (MMA).
  • Homocysteine assesses the need for B vitamins to support methylation. Elevated homocysteine is associated with a higher risk of cardiovascular disease and metabolic syndrome.⁴⁹‍
  • MMA is a more sensitive test for determining B vitamin deficiencies and can identify the risk of underlying metabolic problems.⁵⁰‍
  • Supplement needs: Elevated homocysteine and MMA identifies the need to supplement with B vitamins. For those with elevated homocysteine, a methylated version of a vitamin B supplement will be better for optimal absorption.

• Vitamin D testing: Testing for vitamin D determines if there are adequate levels of this essential nutrient, which plays a critical role in a vast number of bodily functions.‍
  • Supplement needs: Low levels of vitamin D can determine a need for supplementation.  

Below is a summary of some of the core lab tests included in a Function membership and how they are beneficial for understanding the status of overall health:

• Electrolytes: Measures levels of essential electrolytes, such as sodium, potassium, and calcium, to evaluate their balance and overall bodily function.
• Female health: Focuses on hormones, reproductive health markers, and other indicators relevant to women's health and wellness.
• Male health: Assesses hormonal levels, prostate health markers, and other critical indicators for male health and vitality.
• Heart: Evaluates cardiovascular health by assessing key markers such as cholesterol levels, inflammation, and heart disease risk factors.
• Immune regulation: This test examines immune system functionality and inflammation to identify any potential imbalances or autoimmune conditions.
• Kidneys: Evaluates kidney function by measuring markers like creatinine and blood urea nitrogen (BUN), which indicate how well the kidneys are filtering waste from the blood.
• Liver: Assesses liver health by analyzing levels of liver enzymes, bilirubin, and other markers to detect potential liver damage or dysfunction.
• Metabolic: Measures metabolic markers like glucose, insulin, and lipid levels to gauge overall metabolic health and potential risk for metabolic disorders.

Ideal Basic Supplement Regimen

Ideally, the foundations of a supplement regimen should include the basic nutrients of the most common deficiencies. Using these as the base can ensure that all key nutrients are optimized:

Magnesium glycinate or magnesium citrate aids in over 300 biochemical reactions in the body, including muscle relaxation, nerve function, and energy production, while also helping to prevent magnesium deficiency.

• Benefits: Aids in over 300 biochemical reactions, including muscle relaxation, nerve function, and energy production; helps prevent magnesium deficiency.
• Dose: The recommended dose is 300-400 mg per day but can differ depending on the supplement formulation.
• Frequency: Doses are typically taken once daily.
• Mechanism of action: Facilitates numerous enzymatic reactions, supports muscle and nerve function, and helps maintain energy levels.⁵¹

Multivitamins provide a broad spectrum of essential vitamins and minerals to fill dietary gaps and support overall health and well-being.

• Benefits: Provide a broad spectrum of essential vitamins and minerals to fill dietary gaps and support overall health and well-being.
• Dose: The recommended dose might differ depending on the supplement.
• Frequency: Typically, doses are taken once daily.
• Mechanism of action: Supplies essential nutrients to ensure proper physiological function and prevent deficiencies.⁵²

Omega-3 fatty acids (EPA/DHA) support cardiovascular health, reduce inflammation, and promote cognitive function by providing essential fatty acids that the body cannot produce on its own.

• Benefits: Support cardiovascular health, reduce inflammation, and promote cognitive function.
• Dose: The recommended dose is 1-2 grams per day.
• Frequency: Take the dose daily.
• Mechanism of action: Provides essential fatty acids that the body cannot produce, contributing to heart health, reduced inflammation, and improved brain function.⁵³

Probiotics enhance gut health by promoting a balanced microbiome, supporting digestion, and boosting immune function.

• Benefits: Enhance gut health by promoting a balanced microbiome, supporting digestion, and boosting immune function.
• Dose: The recommended dose is 10-20 billion CFUs per day.
• Frequency: Take the dose daily.
• Mechanism of action: Introduces beneficial bacteria to the gut, aiding in digestion and maintaining a healthy balance of intestinal flora.⁵⁴

Vitamin D3 with vitamin K2 enhances calcium absorption for bone health, while vitamin K2 helps ensure calcium is properly utilized and reduces the risk of arterial calcification.

• Benefits: Enhance calcium absorption for bone health; Vitamin K2 ensures proper calcium utilization and reduces the risk of arterial calcification.
• Dose: The recommended dose is 2,000-5,000 IU per day.
• Frequency: Doses are typically taken once daily.
• Mechanism of action: Vitamin D3 increases calcium absorption in the gut; Vitamin K2 directs calcium to bones and teeth while reducing arterial calcification.⁵⁵

Adverse events

An adverse event from a dietary supplement is any negative or unexpected reaction that occurs while taking the product. These events can range from mild issues like an upset stomach to more severe problems, such as allergic reactions or liver damage. The Food and Drug Administration (FDA) defines it as any "health-related event associated with the use of a dietary supplement that is undesirable or unexpected.”⁵⁶ Adverse events are classified as either serious or non-serious, with serious events requiring mandatory reporting to the FDA by manufacturers, even if a direct connection between the supplement and the event has not been confirmed.⁵⁷

For consumers, experiencing an adverse event can be worrying and may suggest that the supplement may not be right for them. Because supplements can affect people differently depending on factors like age, overall health, and other medications taken, it is important to recognize any new or unusual symptoms. If an adverse event occurs, it is encouraged to be reported through the FDA’s MedWatch program, which collects information to help ensure the safety of dietary supplements. Reporting helps the FDA monitor these products and take action if needed, such as issuing warnings or recalls.⁵⁸

Contraindications

A contraindication (CI) is a specific situation where using a supplement could be harmful due to factors like a person’s medical condition, medications, or other individual health considerations. For instance, a supplement might be unsafe for someone with high blood pressure or during pregnancy because of potential risks. Understanding CI is essential for consumers, as taking a supplement under these conditions could lead to adverse effects. By being informed and cautious, consumers can protect themselves from potential harm associated with CI in supplements.¹

Drug-nutrient interactions

Drug-nutrient interactions occur when medications affect the absorption, metabolism, or excretion of nutrients or when nutrients influence the efficacy and safety of medications. Understanding these interactions is important for maintaining optimal health, as they can lead to nutrient deficiencies, reduced drug effectiveness, or increased risk of adverse effects. By being aware of how drugs and nutrients interact, individuals can make informed decisions about their diet and medication use, ensuring balanced nutrition and effective treatment outcomes. Below are some of the drug-nutrient interactions for commonly prescribed medications:

ACE inhibitors, which are commonly used for high blood pressure (including captopril, enalapril, and lisinopril), can lead to nutrient depletions.  

• Nutrient depletion: Medications in this drug class can influence zinc metabolism and lead to a deficiency.⁵⁹
• Supplement recommendation: Zinc, 15-30 mg daily.

Antibiotics are prescribed for various infections and can lead to several nutrient depletions.⁶⁰ Some of these antibiotics include tetracyclines (e.g., doxycycline, minocycline), fluoroquinolones (e.g., ciprofloxacin, levofloxacin), macrolides (e.g., azithromycin, erythromycin), and sulfonamides (e.g., sulfamethoxazole).

• Nutrient depletion: All of these antibiotics can impact the gut microbiome, and some can alter the absorption of important minerals, such as calcium, magnesium, iron, and B vitamins.
• Supplement recommendation: Probiotics, 10-20 billion CFUs daily; Vitamin K, 90-120 mcg daily.

Antidepressants in the SSRI drug class, including fluoxetine and sertraline, can lead to nutrient depletion.⁶¹

• Nutrient depletion: Medications in this drug class can deplete sodium over time.
• Supplement recommendation: Maintain adequate sodium intake through diet.

Calcium channel blockers, which are commonly used for high blood pressure (including nifedipine, amlodipine, and verapamil), can lead to nutrient depletions.

• Nutrient depletion: When taken over time, these medications can lead to folate deficiencies.⁵⁹
• Supplement recommendation: Folic acid at doses between 400-800 mcg per day.

Diuretics (e.g., furosemide, hydrochlorothiazide)

• Nutrient depletion: Diuretics, over time, can cause nutrient deficiencies in potassium, magnesium, and thiamine.⁶²
• Supplement recommendation: Potassium,2,600 mg for women and 3,400 mg for men from combined diet and supplements.Magnesium, 300-400 mg daily.

Metformin is a medication commonly used for insulin resistance or type 2 diabetes to lower blood sugar.

• Nutrient depletion: When taken over time, metformin can lead to deficiencies in vitamin B12.⁵⁹
• Supplement recommendation: Vitamin B12, 500-1,000 mcg daily.

NSAIDs, such as aspirin, are commonly used for self-limiting pain and other health conditions when prescribed by a healthcare provider.⁶³

• Nutrient depletion: NSAIDs, when taken over time, can lead to deficiencies in vitamin C  and iron.
• Supplement recommendation:  Iron, 8 mg daily for men and 8 mg daily for women; Vitamin C, 90 mg for men and 75 mg for women.

Oral contraceptives

• Nutrient depletion: When taken over time, oral contraceptives can lead to deficiencies in folate, vitamins B6 and B12, magnesium, calcium, vitamin C, and vitamin E.⁵⁹
• Supplement recommendation: Folate, 400 mcg daily; Vitamin B6, 2-10 mg daily; Vitamin B12, 500-1,000 mcg daily; Magnesium, 300-400 mg daily.

Proton pump inhibitors, which are commonly prescribed for heartburn or stomach ulcers (including omeprazole and pantoprazole), can lead to nutrient depletions.

• Nutrient depletion: Over time, these medications can deplete vitamin B12, vitamin C, iron, calcium, magnesium, beta-carotene, and zinc.⁵⁹
• Supplement recommendation: Vitamin B12, 500-1,000 mcg; vitamin C, 90 mg for men and 75 mg for women; iron, 8 mg daily for men, 8 mg daily for women; calcium, 1,000 mg for men and women (ages 19-50) or 1,200 mg for women (ages 51 and older) and men (ages 71 and older); magnesium, 300-400 mg; zinc, 15-30 mg.

Statins, such as atorvastatin and simvastatin, are commonly prescribed for high cholesterol and can lead to nutrient depletions.

• Nutrient depletion: Over time, these medications can deplete the levels of CoQ10.⁵⁹
• Supplement recommendation: CoQ10, 100-300 mg daily.

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