Micronutrients, Fluid Balance, Iron, and Supplements Lecture Review

Micronutrients and Fluid Balance

• Today's topic: Micronutrients impacting fluid balance, iron's role in blood health, and supplement overview.

Electrolytes

• Electrolytes are minerals in the body, usually in liquid.
• Salts like sodium chloride (table salt) separate into electrolytes in water.
• Each electrolyte has specific functions.
• Intracellular vs. Extracellular:
  • Potassium: largely inside cells.
  • Sodium: balances potassium outside cells.
  • Calcium and magnesium: balance each other across cell membranes.
• Anions: Negatively charged electrolytes.

Sodium and Fluid Balance

• Focus on sodium's role in fluid balance.
• Movement of electrolytes depends on solute concentration (gradient).

Gradients

• Gradient: level of concentration.
• Going with the gradient:
  • Movement from high to low concentration.
  • Example: People in a packed elevator eager to exit when the doors open.
  • Often doesn't require energy.
• Going against the gradient:
  • Movement from low to high concentration.
  • Example: Forcing oneself into a crowded elevator requires energy.
  • Requires assistance (e.g., sodium-potassium pump) and energy.
  • Sodium-potassium pump moves a solute into area of higher concentration, requires energy.

Sodium (Na+)

• Symbol: Na+
• Abundant in processed/packaged and restaurant food.
• Table salt: Sodium chloride, about 40% sodium, 60% chloride.

Dietary Sources

• High sodium: soups, chips, burgers.
• Low sodium: unprocessed foods (less than 200mg).
• Fruits/vegetables: very low sodium (5-10mg).
• Reduce sodium: focus on minimally processed, plant-based foods.

Functions of Sodium

• Moves micronutrients/macronutrients across cell membranes.
• Aids absorption of glucose and amino acids.
• Nerve conduction (nerve impulses).
• Muscle contraction and normal muscle function.
• Fluid balance.
• Sodium Sensitivity: About 25% of the population is sodium-sensitive.
• Kidneys excrete excess sodium in most people (75%).
• Sodium-sensitive individuals retain more sodium.
• Retention can cause bloating and increased blood volume.
• Increased blood volume may elevate blood pressure.
• Reducing sodium intake can lower blood volume and pressure in sensitive individuals.
• Deficiency is rare, especially in developed countries.
• Possible in those eating unprocessed foods and super athletic individuals losing sodium through perspiration.
• Upper Limit: 2300 mg.
• Exceeding this limit may risk hypertension (high blood pressure).

Sodium in Processed vs. Unprocessed Foods

• Minimally processed/unprocessed foods (5 food groups) have low sodium.
• Processing increases sodium content (e.g., apple to pie, dairy to cheese/soup).
• High sources: soups, condiments, processed items, pizza, lunch meat.
• Monitor sources with sodium sensitivity.
• Unprocessed foods rarely exceed 200 mg sodium naturally.

Iron (Fe)

• Symbol: Fe
• Positive electrolyte.
• Animal sources are more absorbable than plant sources.

Food Sources

• Animal sources: Higher absorption.
• Plant sources: Still good sources of iron.

RDA

• Adult women (below 50, childbearing years): 18 mg/day (to account for menstrual losses).
• Adult men and postmenopausal women: 8 mg/day.
• Significant difference in needs based on gender and life stage.

Heme vs. Non-Heme Iron

• Heme: Animal-based iron (higher absorption).
• Non-Heme: Plant-based iron and eggs (lower absorption).
• Average intake is 12 to 17 mg/day, meeting most people's needs.

Iron Absorption

• Body absorbs more iron when needed (e.g., anemic individuals).
• Plant sources contain fiber, phytates, oxalates that bind iron.
• Vitamin C helps release iron from plant sources.
• Stomach acid is required for iron absorption, decreasing with age.

Iron Storage & Transport

• Ferritin: Storage form of iron in cells, muscles, and liver.
• Transferrin: Transports iron throughout the body.
• Hemoglobin and Myoglobin: Iron in red blood cells for oxygen and carbon dioxide transport.
• Body recycles iron (broken down by liver and spleen).
• Iron losses occur in fecal waste, requiring dietary replenishment.

Iron Deficiency Anemia

• Major micronutrient deficiency, even in developed countries.
• Often due to food choices/lack of information.
• Vegetarians/vegans are at risk if not properly informed.

Stages of Iron Deficiency

• Early stages: No noticeable impact, uses iron stores.
• More deficient: Fatigue, shortness of breath, sluggishness.
• Compromised immune system, frequent colds.
• Advanced stages: Pale skin, more fatigue, constant sickness.
• Severe deficiency in young children: Impacts growth, brain development, and cognition.

Treatment

• Replenishing iron under doctor's care.
• Most individuals recover easily with no long-term impacts.

Other Micronutrients of Interest

Folate and Folic Acid

• Folate: Naturally occurring form.
• Folic acid: Synthetic form, more readily absorbable.

Functions of Folate

• DNA synthesis.
• Amino acid breakdown/building.
• Neurotransmitter synthesis.

Deficiency Conditions

• Neural Tube Defects:
  • Spina bifida: Spinal cord and vertebrae don't fully enclose during fetal development (first month).
  • Folate is required for vertebrae enclosure.
  • Deficiency leads to a sac of spinal fluid protruding.
  • Surgery can remove the sac, but damage during birth is a risk (paraplegia, brain damage, etc.).
  • Government mandated folate enrichment in processed grains to reduce incidence.
• Megaloblastic Anemia:
  • Also known as macrocytic anemia.
  • Related to DNA being impacted.
  • Large, non-functional red blood cells due to DNA division failure.
  • Reduces ability to carry carbon dioxide and oxygen.
  • Can result in folate anemia.

Iodine (I)

• Symbol: I

Food Sources

• Iodized salt (Morton's brand).
• Ocean-based sources: fish (haddock), seaweed.
• Dairy.

Functions of Iodine

• Creation of thyroid hormone.

Deficiency Conditions

• Goiter:
  • Thyroid gland enlargement due to iodine deficiency.
  • Thyroid increases size in the attempt to find iodine.
  • Severe instances require surgery and hormone replacement.
• Cretinism:
  • Occurs during fetal development due to maternal iodine deficiency.
  • Impacts growth and development of the fetus.
  • Causes physical and cognitive impairments.

Toxicity

• Upper limit is 1100 micrograms a day.
• Increases thyroid gland size.

Fluoride (F)

• Symbol: F

Food Sources

• Fluoridated water.
• Seafood.

Functions

• Supports calcium and phosphorus deposition in bones and teeth.

Deficiency Conditions

• Impact on cavities: Weak tooth enamel.
• Lack of fluoride causes tooth decay.

Toxicity

• Modeling: Brown discoloration on teeth due to excess fluoride.
• More common in younger children.

Dietary Supplements

• 50% of US adults take supplements.
• $36 billion annual spending.

Reasons for Supplementation

• Supply essential micronutrients.
• Protection against age-related changes (e.g., synthetic B12).

Dietary Supplemental Health and Education Act (1994)

• Defines supplements: vitamins, minerals, amino acids, plants, etc., taken orally.
• No efficacy or safety proof is required.
• FDA intervenes only when repeated evidence of harm exists.
• No government monitoring for safety or effectiveness.

Claims Made on Dietary Supplements

• Only claims with scientific evidence are allowed (e.g., calcium for osteoporosis risk).
• Can claim it does something as long as it isn't disease associated (e.g. more energy, decreased fat absorption).

Issues

• Lack of government guidelines.
• Mislabeled ingredients (e.g., less vitamin C than claimed).
• Contaminants.
• Lack of standardization.

Examples of Supplement Issues

• Ephedra: Used for fat loss and energy, banned due to heart attacks, strokes, and elevated blood pressure (over 16,000 adverse reactions).
• Buyer beware: Research supplements in advance.

Guidelines

• Diet first, supplement second.
• Supplements should supplement a healthy diet not replace it.

Recommending Supplements

• Lacking nutrients due to dietary choices, allergies, or lack of access.
• Very low calorie diets.

USP Label

• United States Pharmacopeia.
• Non-governmental oversight agency that tests supplements for efficacy and contaminants.
• Look for this label, especially with unrecognized brands.

Things to Consider

• Testimonials are not the best.
• Promises of a quick fix.
• Use best judgment and critical thinking.

Further Thoughts

• More is not better.
• Be careful when mega dosing supplements.
• Combining supplements might create antagonism.

Amino Acid Supplements

• Better to get amino acids from whole food.
• Individual amino acid supplements use the same transporters.
• Potential imbalances might disrupt cell function.
• Should only be supplemented under doctor's care.

Cost Effectiveness of Protein

• Whole food is always the cost-effective form of protein.

Protein Supplementation

• Working the muscles is what increases the strength and mass.
• Increased protein need doesn't mean triple the RRA.
• Too much protein isn't used to build structure or to recover muscles. It's converted to glucose and fat, while nitrogen is removed.
• Can cause excess water loss, kidney issues, acidic environment which causes the leaching of calcium from bone.

Closing Thoughts

• Be a critical consumer.
• Prioritize whole foods.
• Supplementation is okay but isn't an excuse to eat poorly.