A Complete Guide to Bone Health For Women

As a dietitian who has worked with hundreds of women, it genuinely worries me how often bone health is treated as an afterthought. We talk about calories, protein, weight loss, hormones, gut health and skin health, but rarely about the skeleton that is literally holding us up.

According to the International Osteoporosis Foundation, around 1 in 3 women over the age of 50 will experience an osteoporosis-related fracture in their lifetime.

For too many women, bone health only becomes a priority after a fracture, when the real opportunity was years earlier.

How Bone Works: The Basics

Bone is living tissue. It's constantly being broken down and rebuilt in a process called bone remodelling. Specialised cells called osteoclasts break down old bone, and osteoblasts build new bone to replace it.

In your 20s, bone building outpaces breakdown. This is how you accumulate peak bone mass, the maximum density your skeleton will ever reach. Most women hit peak bone mass around age 25–30.

After that, the balance gradually shifts. Breakdown begins to outpace building, and bone density slowly declines. This is a normal part of ageing, but how steep that decline is depends heavily on lifestyle, nutrition, and hormonal status.

Why Women Are at Higher Risk

Women face a higher risk of osteoporosis than men for several reasons:

• Smaller, less dense bones to begin with. Women naturally have lower peak bone mass than men.
• Oestrogen decline at menopause. Oestrogen plays a key role in slowing bone breakdown. When it falls sharply at menopause, bone loss accelerates. Women can lose up to 20% of bone density in the five to seven years around menopause.
• Longer life expectancy. More years means more time for bone loss to accumulate.
• History of dieting and restriction. Chronic under-eating is one of the most significant, and underacknowledged, risk factors for low bone density in women.

Bone Health Across Life Stages

In Your 20s: Build the Foundation

Your 20s are your bone-building prime. The goal at this stage is to reach the highest possible peak bone mass, because the density you accumulate now is what you draw on for the rest of your life.

Priorities:

• Eat enough. Chronically under-fuelling in your 20s directly impairs bone building
• Hit your calcium targets daily (see calcium section below)
• Supplement vitamin D, especially from October to March if you live in Ireland or the UK
• Start resistance training and make it a habit

In Your 30s: Maintain and Protect

Bone building starts to slow in your early 30s. You're not in crisis territory, but this is the decade where good habits either stick or start to slip. Women who have spent years restricting food or avoiding strength training may already begin to see the effects.

Priorities:

• Continue consistent resistance training
• Prioritise protein at every meal to maintain muscle mass
• Keep calcium and vitamin D intake consistent
• Get baseline bone density checked if you have risk factors (history of disordered eating, very low body weight, long-term amenorrhoea)

In Your 40s: Perimenopause and Accelerating Loss

Perimenopause, the years leading up to the final menstrual period, begins in the early-to-mid 40s. Oestrogen starts to fluctuate and decline, and with it, the rate of bone loss increases. Many women don't realise they're in perimenopause, and don't realise their bone health is changing along with it.

Priorities:

• Have an honest conversation with your GP about hormone replacement theray (HRT). The evidence on HRT and bone protection has shifted significantly and it's worth discussing
• Increase resistance training load if you haven't already
• Pay close attention to protein and calcium intake, needs increase as absorption efficiency declines
• Get a DEXA scan (bone density scan) to establish a baseline

In Your 50s and Beyond: Slow the Loss

Post-menopause, the focus shifts from building to protecting. You cannot significantly rebuild lost bone, but you can meaningfully slow further loss and reduce fracture risk through nutrition, exercise, and medication where appropriate.

Priorities:

• Continue resistance training. It remains the single most effective non-pharmaceutical intervention for bone density.
• Review your calcium intake carefully; many post-menopausal women fall short.
• Discuss medications (bisphosphonates, denosumab, HRT) with your GP if your DEXA scan shows osteopenia or osteoporosis.
• Focus on fall prevention. Focus on balance training, strength, and ensuring a safe home environment.

Calcium: How Much You Need and How to Get It

Calcium is the primary mineral in bone. About 99% of the body's calcium is stored in the skeleton, and when dietary intake is insufficient, the body draws calcium from bone to maintain blood levels. Over time, this weakens bone structure.

How Much Calcium Do You Need?

Most women in Ireland and the UK fall short of these targets, particularly post-menopausal women.

Best Food Sources of Calcium

Dairy (highest bioavailability):

• Milk (240ml): ~300 mg
• Plain yoghurt (150g): ~200–250 mg
• Hard cheese such as cheddar (30g): ~200 mg
• Cottage cheese (100g): ~60–80 mg

Non-dairy sources:

• Fortified plant milks (240ml): ~120–300 mg (check the label — varies significantly by brand)
• Canned salmon with bones (100g): ~200–250 mg
• Canned sardines with bones (85g): ~350 mg
• Cooked kale (100g): ~150 mg
• Cooked broccoli (100g): ~40 mg
• Tofu set with calcium sulphate (100g): ~200–300 mg
• White beans / cannellini beans (100g cooked): ~90 mg
• Almonds (30g): ~75 mg
• Fortified bread or cereals: varies, check label

Bone Health Friendly Recipes

• Mediterranean Sardine Salad
• Sardine Puttanesca
• Greek Yogurt Fruit Dip
• Chia Seed and Yogurt Pudding
• Snickers Yogurt Cups
• Creamy Overnight Oats

A Note on Plant-Based Calcium

You can meet your calcium needs on a dairy-free or plant-based diet, but it requires planning. Absorption rates vary. The calcium in milk is absorbed at around 30–35%, while some plant sources are lower. Spinach, for example, contains calcium but also oxalates that inhibit absorption, making it a poor calcium source despite how it's often portrayed.

If you've removed dairy from your diet, you need to actively replace it. Oat milk without added calcium does not replace the calcium in dairy milk.

Calcium Supplements

Supplements are an option if you consistently can't meet your needs through food, but food sources are preferred where possible. If supplementing, calcium carbonate is best taken with food; calcium citrate can be taken without food and is better absorbed by those with lower stomach acid (more common post-menopause).

There has been some debate about calcium supplements and cardiovascular risk. Discuss with your GP if you have concerns, particularly at higher doses.

Vitamin D: The Absorption Key

Vitamin D is essential for calcium absorption. Without adequate vitamin D, your body cannot properly absorb the calcium you consume regardless of how good your diet is.

Vitamin D and Bone Health

Vitamin D stimulates calcium absorption in the gut and helps regulate calcium and phosphorus levels in the blood. Deficiency leads to lower bone mineral density and increased fracture risk over time.

Are You Getting Enough?

In Ireland and the UK, UV radiation from sunlight is insufficient to produce meaningful vitamin D through the skin from October to March. During these months, dietary and supplemental sources are the only reliable options.

Foods containing vitamin D include:

• Oily fish (salmon, mackerel, sardines)
• Egg yolks
• Fortified dairy and plant milks
• Some fortified breakfast cereals

However, it's very difficult to meet vitamin D needs through food alone. The Irish and UK governments recommend that all adults consider a vitamin D supplement of 10–15 mcg (400–600 IU) daily, particularly from October to March.

If you suspect deficiency, a blood test (25-hydroxyvitamin D) can confirm your levels. Many women are surprised to find they're significantly low.

Who Needs to Be More Careful

• Anyone living at northern latitudes (Ireland, UK, Scandinavia)
• People who cover their skin for cultural or religious reasons
• People with darker skin tones (more melanin reduces vitamin D synthesis)
• Older adults (skin becomes less efficient at producing vitamin D with age)
• People who spend most of their time indoors

Exercise: What Actually Builds Bone

This is one of the most misunderstood areas of bone health. Exercise is essential for bone density, but not all exercise has the same effect.

Why Bone Responds to Load

Bone remodels in response to mechanical stress. When you place load on the skeleton through resistance training or weight-bearing impact, specialised bone cells sense that stress and respond by building new bone to meet the demand.

No load, no signal. No signal, no new bone.

What Counts

Resistance training (most effective) Lifting weights, using resistance machines, or bodyweight exercises like squats, lunges, and push-ups all apply mechanical load to the skeleton. Resistance training is the most evidence-backed non-pharmaceutical intervention for maintaining and improving bone density. Both the upper and lower body benefit from targeted training.

Weight-bearing impact exercise Running, jumping, dancing, and team sports all apply impact forces to the skeleton and support bone health. Higher-impact activities are generally more osteogenic (bone-stimulating) than low-impact ones.

What doesn't build bone Swimming and cycling are excellent for cardiovascular health and are appropriate for women with joint issues or injuries, but they are non-weight-bearing and do not meaningfully stimulate bone formation. A woman who has walked or cycled daily for decades may still have low bone density if she has never done resistance training.

How Much Exercise?

Current guidance recommends:

• 2–3 sessions of resistance training per week, targeting major muscle groups
• Weight-bearing activity most days. This can include walking, but should ideally include higher-impact movement where joints allow
• Balance training from your 40s onwards to reduce fall risk

If you're new to resistance training, starting with a qualified trainer is worthwhile, particularly post-menopause when technique matters more to avoid injury.

Diet Beyond Calcium: What Else Matters for Bone

Protein

Bone is made of collagen (protein) and calcium. Protein intake directly supports bone matrix formation, and low protein intake is associated with lower bone density and higher fracture risk.

Protein also supports muscle mass, which protects bone indirectly. Muscles pull on bone during movement, helping to maintain density.

Aim for adequate protein at every meal. Good sources include:

• Eggs
• Meat and poultry
• Fish and seafood
• Greek yoghurt and cottage cheese
• Legumes (lentils, chickpeas, beans)
• Tofu and tempeh

General guidance for women is around 1.2–1.6g of protein per kilogram of body weight per day, with higher intakes being increasingly supported in older women and those who are active.

Magnesium

Magnesium plays a role in bone mineralisation and vitamin D metabolism. It's found in leafy greens, nuts, seeds, legumes, and wholegrains. Most people who eat a varied diet get enough, but those who eat highly processed diets may fall short.

Vitamin K2

Vitamin K2 helps direct calcium into bone and away from soft tissue. It's found in fermented foods and some animal products. Research is still emerging, but it's worth including K2-rich foods such as cheese, egg yolks, and fermented soy in your diet.

What to Limit

• Excessive alcohol: More than 2 units per day is associated with reduced bone density and increased fracture risk.
• Smoking: Smoking directly impairs bone formation and is a significant independent risk factor for osteoporosis.
• Very high caffeine intake: Extremely high caffeine consumption may slightly reduce calcium absorption, though moderate intake (1–3 cups of coffee per day) is unlikely to be a concern for women who meet their calcium targets.
• Crash dieting: Rapid, severe calorie restriction impairs bone metabolism. Chronic under-eating across years or decades is one of the most damaging things for long-term bone health.

Common Myths About Bone Health

"I'll worry about my bones when I'm older." Peak bone mass is set by your late 20s. By the time osteoporosis appears on a scan, decades of bone loss have already occurred. Prevention starts in your 20s and 30s, not your 60s.

"I drink plant milk, so I'm getting enough calcium." Only if your plant milk is fortified with calcium and even then, you need to be checking how much. Many plant milks contain significantly less calcium than dairy milk, and some contain very little. Always check the label.

"I walk every day, so my bones are fine." Walking is good for you. It is not enough to build or maintain bone density on its own. Resistance training is what the research consistently shows makes the difference.

"Dairy causes inflammation, so I cut it out." The evidence does not support dairy as a cause of systemic inflammation in people without a diagnosed allergy or intolerance. If you feel fine eating dairy, there is no evidence-based reason to remove it and doing so without replacing the calcium is actively harmful to bone health.

"Calcium supplements are just as good as food." Calcium from food comes packaged with co-nutrients (protein, phosphorus, vitamin D in fortified dairy) that support absorption and utilisation. Supplements are a backup, not a first-line strategy.

When to See Your GP or a Registered Dietitian

Consider speaking to your GP about bone health if you:

• Are approaching or past menopause
• Have a personal or family history of fractures
• Have had long periods of amenorrhoea (missing periods)
• Have a history of disordered eating or significant calorie restriction
• Take medications that affect bone (such as corticosteroids)
• Have coeliac disease, inflammatory bowel disease, or other conditions affecting nutrient absorption

A DEXA scan is the gold standard for measuring bone density. It's a low-radiation, non-invasive scan and is available through your GP if you have risk factors.

A registered dietitian can help you audit your calcium and vitamin D intake, identify gaps, and build a practical eating plan that supports bone health at your specific life stage.

Key Takeaways

• Bone health is built over decades. The habits you have now matter regardless of your age.
• Peak bone mass is set by your late 20s; the focus after that is maintenance and slowing loss.
• Calcium (1,000–1,200mg/day depending on life stage) and vitamin D (supplement from October–March in Ireland and the UK) are non-negotiable.
• Resistance training is the most effective exercise for bone density, cardio alone is not sufficient.
• Adequate protein supports both bone and muscle, which protect each other.
• Menopause is the highest-risk period for bone loss; HRT is worth discussing with your GP.
• Chronic calorie restriction, smoking, and excessive alcohol are some of the most damaging lifestyle factors.