1. SUBJECT : HUMAN NUTRITION
PRESENTED BY,
MEGHA T P
MSC FOOD & NUTRITION

2. 
 INTRODUCTION
 FUNCTIONS OF CALCIUM
 SOURCES OF CALCIUM
 BIOAVAILABILITY OF CALCIUM
 FACTORS ENHANCE CALCIUM
BIOAVAILABILITY
 FACTORS REDUCE CALCIUM BIOAVAILABILITY
 STRATEGIES FOR OPTIMIZING CALCIUM
BIOAVAILABILITY.
CONTENTS

3. 
 Calcium is the major element in the body.
 Almost 99% of calcium is found in the hard tissues of
the body-namely the bones and teeth.
 The rest is distributed in blood and soft tissues, such
as muscles, liver and heart.
 Calcium comprises 39.9% of weight of bone mineral.
 Ca is required for growth because it forms an
important part of bones and teeth and is required in
smaller amounts for the proper functioning of every
cell in the body.
INTRODUCTION

4. 
 Blood clotting : Thromboplastin, catalyses the
conversion of the protein prothrombin(present in the
blood) into thrombin, that process required Ca ions.
 Calcium as intracellular messenger : Certain hormones
exert their action through the mediation of calcium. Ca
is regarded as a second messenger for such hormones.
 Release of hormones : The release of certain hormones
from endocrine glands is facilitated by Ca2+.
 Action on heart : Ca2+ act on myocardium and
prolongs systole.
FUNCTIONS OF CALCIUM

5.  Membrane integrity and permeability : Ca2+ ion
influences the membrane structure and transport of
water and several ions across it.
 Activation of enzymes : Ca2+ is needed for the direct
activation of enzymes such as lipase, ATPase, and
succinate dehydrogenase
 Ca involved in the absorption of vitamin B12.
 Bone & tooth formation.
 Required for growth.

6. 
 Ca is present in both animal and plant foods.
 The richest source of calcium among animal food is
milk and among vegetable source is green leafy
vegetables.
 Dairy foods are major source of calcium beauce of the
significant amount of minerals present.
 Among leafy vegetables , amaranth, fenugreek and
drumstick leaves are particularly rich in calcium.
 Most cereals and millets contain some amounts.
 Ragi is rich source of calcium.
SOURCES OF CALCIUM

7. 
 Calcium bioavailability refers to the amount of
calcium from a food or supplement that is absorbed
and available for use by the body.
 Several factors can affect calcium bioavailability
including the type of food or supplement consumed ,
presence of other nutrients , and individual
differences in absorption and metabolism.
 Factors that can enhance calcium bioavailability
include vitamin D , solubility ,an acidic environment
and lactose.
BIOAVAILABILITY OF CALCIUM

8.  Factors that can reduce calcium bioavailability include
phytates and oxalates , high fibre diets , age and
medications.
 Optimising calcium bioavailability is important for
maintaining strong bones and teeth , and overall health
and well being.
 Strategies for optimising bioavailability include
consuming a varied diet that includes calcium rich
foods , taking vitamin D supplements avoiding excess
consumption of phytites and oxalates.

9. 
 Type of food or supplement : Different type food or
supplement contain varying amounts and forms of
calcium , which can affect how much calcium is
absorbed by the body.
 Vitamin D : it helps the body to absorb and use
calcium more affectively. The presence of the active
form of vitamin D (1-25 dihydroxy cholecalciferol) can
result in a 10-30 % increase in calcium absorpsion.
 Solubility : Calcium in more soluble form , such as
calcium citrate is generally more bioavailable than less
soluble forms such as calcium carbonate.
FACTORS ENHANCE CALCIUM
BIOAVAILABILITY

10.  Acidic environment : Calcium absorption is
enhanced in an acidic environment , so consuming
calcium rich food with meals or drinks that contain
acid(eg : Orange juice) can include bioavailability.
Anything that increases the acidity of digestive mass
before it enters the small intestine prolongs the time
take for the neutralisation occurs and so increases
efficiency of calcium absorption.
 Lactose : A sugar found in milk and diary product
can enhance calcium absorption.

11. 
 Phytates & Oxalates : These compounds found in
some plant foods like spinach and beans , can bind to
calcium and reduce its absorption.
 High fiber diets : Its can decrease calcium absorption
by increasing the amount of calcium excreted in the
faeces.
 Age : Ca absorption tents to decrease with age
particularly after menopause.
 Medications : Some medications , such as
corticosteroids and antacids , can interfere with Ca
absorption.
FACTORS REDUCE CALCIUM
BIOAVAILABILITY

12. 
 Consume calcium rich foods : Eating a varied diet
that include calcium rich foods such as milk and
other diary products , leafy green vegetables ,
fortified and calcium set tofu can help ensure
adequate calcium intake.
 Take Vitamin D supplements : Vitamin D helps the
body absorbe and use calcium more affectively , so
taking vitamin D supplements or getting enough
vitamin D from sunlight exposure can help optimize
calcium bioavailability.
STRATEGIES FOR OPTIMIZING
CALCIUM BIOAVAILABILITY

13.  Chose calcium supplement wisely : Ca supplement
can be an option for people who have trouble getting
enough Ca from their diets , but it is important to
choose supplements that are easily absorbed and
tolerated , such as calcium citrate or calcium lactate.
 Avoid excess consumption of phytates and oxalates :
Limiting intake of these compounds or pairing
calcium rich foods with other nutrients that enhance
calcium absorption can help optimize bioavailability.
 Limit intake of substances that interfere with Ca
absorption : Some substances such as caffeine ,
excess sodium and alcohol can interfere with Ca
absorption.
 Consume calcium rich foods with acidic foods or
drinks

14. 
 https://chat.openai.com/
 https://academic.oup.com/nutritionreviews/article
 Nutrition science – B Srilaksmi – 5th multicolour
edition .
REFERENCE

15. THANK YOU